WO1998005539A1

WO1998005539A1 - Brake force control device

Info

Publication number: WO1998005539A1
Application number: PCT/JP1997/002509
Authority: WO
Inventors: Masahiro Hara; Satoshi Shimizu
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 1996-08-02
Filing date: 1997-07-18
Publication date: 1998-02-12
Also published as: DE69718005T2; JPH1095327A; AU3558697A; US6293633B1; DE69726472D1; EP0918004B1; JP3287259B2; DE69726472T2; EP1182107B1; DE69718005D1; EP0918004A1; EP0918004A4; EP1182107A1

Abstract

A brake force control device realizes both BA control, in which a great brake force is generated when an emergency braking operation is performed, and ABS control for controlling a slip rate of wheels, and prevents interference between BA control and ABS control. When BA control is judged to be started (step 100, 102), whether ABS control is executed for one or more front wheels (step 104) is judged. In the case where ABS control is executed for one or more front wheels, it is judged that a large amount of liquid pressure will be supplied to wheel cylinders of rear wheels simultaneously with starting of BA control, and BA gradient suppression control for inhibiting inflow of the liquid pressure is started (step 108). In the case where ABS control is not executed on the front wheels, a normal BA control is started (step 106).

Description

Description Braking force control device Technical field

The present invention relates to a braking force control device, and more particularly to a braking force control device suitable as a device for controlling a braking force generated by a vehicle braking device. Background art

Japanese Patent Application Laid-Open No. 4-1212600 discloses a braking force control device having a brake assist function and an anti-lock brake function. The brake assist function (hereinafter referred to as the ABS function) is provided to generate a larger brake oil pressure than usual when an emergency brake operation is performed by the driver. The anti-lock brake function (hereinafter referred to as the ABS function) is used to control the wheel cylinder pressure P w / c of each wheel so that an excessive slip rate does not occur on each wheel during the braking operation. Provided.

The conventional braking force control device that realizes the ABS function controls the master cylinder that generates the brake fluid pressure according to the brake depression force, the conduction state between the master cylinder and each wheel, and the conduction state between the reservoir tank and each wheel. And a hydraulic circuit for performing the operation. In the hydraulic circuit, the foil cylinder that needs to increase the foil cylinder pressure P w / c is conducted to the mass cylinder, and the foil cylinder that needs to reduce the foil cylinder pressure P _{w / C} is conducted to the reservoir tank. It is controlled to make it. According to the above control, the wheel cylinder pressure P w / c of each wheel can be appropriately controlled in a range lower than the braking fluid pressure generated by the master cylinder.

The conventional braking force control device that realizes the BA function is based on a high-pressure source that generates a predetermined hydraulic pressure regardless of the brake depression force, and a hydraulic pressure generated by the high-pressure source And a hydraulic pressure control valve for reducing the pressure and supplying it to the wheel cylinder of each wheel. The hydraulic pressure control valve supplies the brake fluid pressure, which is boosted at a predetermined boosting ratio to the brake depression force, to each wheel when the driver does not perform the emergency brake operation. Further, when the driver performs an emergency braking operation, the hydraulic pressure control valve supplies the brake fluid of the maximum hydraulic pressure generated by the high pressure source to the wheel cylinder of each wheel ₍ according to the above processing, When a normal brake operation is performed by the driver, a wheel cylinder pressure P _{w / C} corresponding to the brake depression force can be supplied to the wheel cylinder of each wheel. Is executed, the wheel cylinder pressure of each wheel can be supplied with a higher wheel cylinder pressure P w, c than usual. However, the function as a normal brake and the BA function can be appropriately realized.

As a braking force control device that realizes both the BA function and the ABS function, for example, the brake fluid pressure generated by the master cylinder and the brake fluid pressure generated by the high pressure source are selectively supplied to the upstream side of the hydraulic circuit. in obtaining device _c according braking force control device considered, ABS function is achieved by while supplying hydraulic pressure generated more master serial Sunda hydraulic circuit, for controlling the hydraulic circuit in the above-described method . The BA function is realized by supplying the brake fluid pressure generated by the high-pressure source to the wheel cylinder of each wheel via the fluid pressure circuit while the master cylinder and the fluid pressure circuit are shut off. Hereinafter, control for realizing the BA function in the above braking force control device is referred to as BA control, and control for realizing the ABS function is referred to as ABS control.

In the above-described braking force control device that realizes both the BA function and the ABS function, when the BA control is started, an excessive slip rate may occur on any of the wheels. In this case, if the ABS control is executed for the wheel, the BA function and the ABS function can be realized at the same time. You. This function is to supply the hydraulic circuit with the brake fluid pressure generated by the high-pressure source and to connect the wheel cylinder of the wheel with the excessive slip ratio to the reservoir tank side as appropriate. This can be achieved by controlling the voltage circuit. Hereinafter, the above function is referred to as the BA + ABS function, and the control for realizing the BA + ABS function is referred to as the BA + ABS control. << According to the BA + ABS control described above, the driver performs emergency brake operation. after but executed while increased or decreased according to Hui Rushiri Nda圧Pw / _C of the wheel caused excessive Slip rate requirements of the ABS control, BA control Hoirushiri Nda圧P _{w / C} of other wheels The pressure can be increased as required.

However, during execution of BA + ABS control, interference occurs between BA control and ABS control. That is, during the execution of the BA + ABS control, an environment different from the case where the BA control is executed alone and the environment where the ABS control is executed alone is formed. For this reason, when performing BA + ABS control, if BA control and ABS control are executed in the same way as when they are executed independently, a situation may occur where the wheel cylinder pressure Pw / c cannot be properly controlled. obtain.

In other words, during the execution of BA + ABS control, the wheel cylinder of the target wheel of the ABS control (hereinafter referred to as the ABS target wheel) must be increased in wheel cylinder pressure P _{w / C} for that wheel. It needs to be disconnected from the high pressure source for a short time. On the other hand, the high pressure source is given sufficient capacity to increase the wheel cylinder pressure Pw / c of all four wheels with an appropriate pressure gradient after the BA control is started. For this reason, during the execution of the BA + ABS control, the change rate of the wheel cylinder pressure Pw / _{C with} respect to the non-target wheels of the ABS control (hereinafter referred to as ABS non-target wheels) is determined by the BA control being executed independently. The pressure increase gradient becomes sharper than in the case.

When the ABS control is executed independently, the master cylinder pressure PM _{/ C} is supplied to the wheel cylinder of the ABS target wheel. This On the other hand, during the execution of the BA + ABS control, the hydraulic pressure generated by the high pressure source is supplied to the wheel cylinder of the ABS target wheel. The high pressure source generates a higher hydraulic pressure than the hydraulic pressure that normally occurs as the mass cylinder pressure PM _{/ C.} For this reason, the change rate of the wheel cylinder pressure P w / c of the ABS target wheel tends to have a sharp pressure increase gradient during the execution of the BA + ABS control compared to the case where the ABS control is executed alone. .

The wheel cylinder pressure Pw / c of the wheel subject to ABS is reduced when an excessive slip ratio occurs in the wheel, and then is increased relatively slowly. If the wheel cylinder pressure Pw / _C is increased with a steep pressure gradient during this pressure increase, the wheel cylinder pressure Pw / c is immediately increased after the wheel cylinder pressure Pw / c starts increasing. _It is necessary to reduce the pressure of _{w / C.} For this reason, if the wheel cylinder pressure P _{w / C} is increased with a steep pressure increase gradient as described above during the execution of the BA + ABS control, hunting in the control of the ABS target wheel occurs. It will be easier.

As described above, when the BA + ABS function is to be realized by the above-described method, the BA control and the ABS control interfere with each other, and hunting in control is likely to occur on the ABS target wheel. There is a problem that an excessive pressure increase gradient is generated on the non-target wheels (the target wheels for BA control). In this regard, the above-described method is not always the optimal method for realizing the BA + ABS function. Disclosure of the invention

A general object of the present invention is to provide an improved and useful braking force control device which solves the above-mentioned problems.

A more specific object of the present invention is to provide a braking force control device capable of preventing interference between BA control and ABS control and appropriately achieving both BA + ABS functions.

In order to achieve the above object, according to one aspect of the present invention, a foil cylinder pressure is reduced while a hydraulic pressure inflow path to a wheel cylinder is blocked. A braking force control device that performs brake fluid pressure reduction control to control and brake assist control to generate a larger brake fluid pressure than normal when an emergency brake operation is performed by a driver.

A continuity detecting means for detecting a continuity state of the hydraulic pressure inflow path of the foil cylinder;

At the start of the brake assist control, if the hydraulic pressure inflow path of any one of the wheel cylinders is substantially blocked, the hydraulic pressure inflow suppression means for suppressing the inflow of the brake hydraulic pressure to another wheel cylinder When,

A braking force control device comprising:

In the above-described invention, when the brake fluid pressure reduction control is executed for any of the wheel cylinders, the flow of the brake fluid pressure into the foil cylinder is prevented. For this reason, when the brake assist control is started in such a situation, a situation occurs in which the brake fluid pressure to be supplied to the foil cylinder whose fluid pressure inflow path is shut off is distributed to other foil cylinders. The hydraulic pressure inflow suppressing means prevents the brake hydraulic pressure from being excessively guided to another wheel cylinder in such a situation.

Therefore, according to the above-described invention, even if the brake assist control is started in a state where the hydraulic pressure inflow path of any of the foil cylinders is interrupted, the brake fluid is excessively applied to the foil cylinder whose hydraulic pressure inflow path is not interrupted. Pressure can be prevented from being introduced. Therefore, according to the braking force control device of the present invention, excellent controllability can be maintained even in such a situation.

Further, according to another aspect of the present invention, when the characteristic value related to the slip state of the wheel exceeds a predetermined threshold, the hydraulic pressure inflow path communicating with the wheel cylinder of the wheel is cut off. After executing the pressure reduction control for reducing the wheel cylinder pressure for a predetermined period, the brake hydraulic pressure control for executing the predetermined hydraulic pressure control for the wheel cylinder and the normal operation when an emergency brake operation is performed by the driver. In a braking force control device that performs a brake assist control that generates a relatively large braking fluid pressure, A continuity detecting means for detecting a continuity state of the hydraulic pressure inflow path of the foil cylinder;

When the brake assist control is started in a state where the hydraulic pressure inflow path of any one of the foil cylinders is substantially blocked, the pressure reduction control is executed for the at least one other wheel cylinder. Means for changing the decompression tendency, which increases the decompression tendency caused by

A braking force control device comprising:

In the above-mentioned invention, when the hydraulic pressure inflow path is shut off for any of the wheel cylinders, the inflow of the brake hydraulic pressure into the wheel cylinder is prevented. For this reason, when the brake assist control is started in such a situation, the fluid pressure in the other wheel cylinders rises more sharply than when the fluid pressure inflow paths of all the wheel cylinders are conducting. Tends to occur. In the present invention, after the pressure reduction control is started, the pressure of the foil cylinder of the other one of the foil cylinders is greatly reduced as compared with the normal state. For this reason, the foil cylinder pressure of the other foil cylinder does not unnecessarily increase even if the hydraulic pressure inflow path of any one of the foil cylinders is blocked.

Further, the braking force control device according to the present invention includes:

When the brake assist control is started in a state where the hydraulic pressure inflow path of any one of the wheel cylinders is substantially blocked, the threshold value of at least the other wheel cylinder is compared with a normal state. Means for changing the threshold value to a smaller value May be provided.

In the present invention, when the brake assist control is started in a state where the hydraulic pressure inflow path is shut off for any of the wheel cylinders, the wheel cylinder pressures of the other wheel cylinders become transiently higher than normal. easy. The threshold value changing means changes the threshold value in such a situation so that the pressure reduction control is easily started for another foil cylinder. For this reason, the foil cylinder pressure of other foil cylinders does not become an unnecessarily high fluid pressure, though it rises sharply compared to normal times.

Therefore, according to the above-mentioned invention, even if the brake assist control is started in a state where the hydraulic pressure inflow path of any of the wheel cylinders is interrupted, excessive braking fluid is applied to the foil cylinder whose hydraulic pressure inflow path is not interrupted. Pressure can be prevented from being introduced. Therefore, according to the braking force control device of the present invention, excellent controllability can be maintained even in such a situation.

According to another aspect of the present invention, when the driver performs an emergency braking operation, the brake assist control that generates a larger braking oil pressure than usual, and the braking oil pressure of each wheel is controlled by each wheel. The anti-braking brake control, which controls the pressure so as not to generate an excessive slip rate, and the braking force control device, which performs

Operating hydraulic pressure generating means for generating a braking hydraulic pressure according to the brake operating amount; assist pressure generating means for generating a predetermined braking hydraulic pressure irrespective of the brake operating amount;

A high-pressure passage communicating with both the operating hydraulic pressure generating means and the assist pressure generating means;

An operating hydraulic pressure shut-off mechanism that can shut off the operating hydraulic pressure generating means and the high-pressure passage;

A low-pressure passage communicating with a predetermined low-pressure source;

Conduction state between the wheel cylinder of each wheel and the high-pressure passage, and A conduction state control mechanism for controlling a conduction state between the wheel cylinder of each wheel and the low-pressure passage;

BA control means for shutting off the operating hydraulic pressure cut-off mechanism when an emergency brake operation is performed by a driver, and for supplying predetermined brake hydraulic pressure to the high-pressure passage from the assist pressure generating means; ABS control means for controlling the wheel cylinder pressure of each wheel by controlling the conduction state control mechanism in a predetermined control pattern so that an excessive slip rate does not occur in each wheel.

When the anti-lock brake control is executed independently, the control pattern is set to the normal pattern, and when the anti-lock brake control and the brake assist control are simultaneously executed, the control pattern is set to the wheel cylinder pressure. ABS control pattern selecting means for setting the pressure increase amount suppression panel for suppressing the pressure increase amount;

A braking force control device comprising:

In the above invention, when an excessive slip ratio occurs in any of the wheels without the driver performing the emergency braking operation, the antilock brake control (hereinafter, ABS control) is started independently. You. In this case, the wheel cylinder pressure of each wheel is increased when the wheel cylinder and the operating fluid pressure generating means are brought into conduction. The normal pattern of the ABS control is set such that when the wheel cylinder pressure is increased in such a situation, an appropriate pressure increase is generated in the wheel cylinder pressure.

If an emergency brake operation is performed by the driver before the ABS control is started, the brake assist control (hereinafter referred to as BA control) is started. During the execution of the BA control, the operating hydraulic pressure generating mechanism is disconnected from the high pressure passage by the operating hydraulic pressure cutting mechanism, and the assist pressure generating means supplies a predetermined brake hydraulic pressure to the high pressure passage. In this case, the wheel cylinder pressure of each wheel is rapidly increased by using the assist pressure generating means as a hydraulic pressure source due to the closing of the operating hydraulic pressure cutting mechanism. If the slip ratio of each wheel becomes excessive with the start of BA control, then it is necessary to execute BA control and ABS control simultaneously, that is, execute BA + ABS control. Becomes If the BA control is started prior to the execution of the ABS control, the ABS control is performed under the condition that the high brake fluid pressure generated by the assist pressure generating means is guided to the high pressure passage. In the present invention, in such a situation, the ABS control is executed according to the pressure increase amount suppression pattern. For this reason, despite the fact that a higher brake fluid pressure is introduced into the high-pressure passage than usual, an excessive increase in the wheel cylinder pressure of the ABS target wheel does not occur.

Therefore, according to the above-described invention, when the ABS control and the BA control are performed simultaneously, the fact that an excessive pressure increase is applied to the wheel cylinder pressure of the ABS target wheel, that is, the ABS control It is possible to prevent a situation where hunting easily occurs from being formed.

Further, according to another aspect of the present invention, when an emergency braking operation is performed by a driver, a brake assist control that generates a larger braking oil pressure than usual, and a braking oil pressure of each wheel is set to each wheel. The anti-braking brake control, which controls the pressure so as not to generate an excessive slip rate, and the braking force control device, which performs

Operating hydraulic pressure generating means for generating a brake hydraulic pressure according to the brake operating amount; assist pressure generating means for generating a predetermined brake hydraulic pressure irrespective of the brake operating amount;

A low-pressure passage communicating with a predetermined low-pressure source;

The conduction state between the wheel cylinder of each wheel and the high pressure passage and the conduction state between the wheel cylinder of each wheel and the low pressure passage are controlled. Communication state control mechanism,

BA control means for shutting off the operating hydraulic pressure cut-off mechanism when an emergency brake operation is performed by a driver, and for supplying predetermined brake hydraulic pressure to the high-pressure passage from the assist pressure generating means; ABS control means for controlling the wheel cylinder pressure of each wheel by controlling the conduction state control mechanism in a predetermined control pattern so that an excessive slip rate does not occur in each wheel;

When the brake assist control and the anti-lock brake control are simultaneously executed, the pressure increase gradient of the wheel cylinder pressure of the non-target wheel of the anti-lock brake control is suppressed so as to suppress the gradient. BA pressure increase gradient suppression means for controlling the conduction state control mechanism provided

A braking force control device comprising:

In the above invention, when the driver performs an emergency brake operation, the BA control is started. During the execution of the BA control, the wheel cylinder pressure of each wheel is increased using the assist pressure generating means as a hydraulic pressure source. The assist pressure generating means is provided with the ability to generate an appropriate pressure increasing gradient to the wheel cylinder pressure P w / c of all the wheel cylinders communicating through the high pressure passage.

After the BA control is started, if an excessive slip ratio is detected for any of the wheels, the BA + ABS control is started. The wheel cylinder of the wheel subject to ABS is shut off from the high-pressure passage except for a short time during which the wheel cylinder pressure of the wheel needs to be increased by the ABS control. Therefore, during the execution of the BA + ABS control, almost all of the brake fluid discharged from the assist pressure generating means is supplied to the wheel cylinders of the non-ABS wheels. In the present invention, when such a situation is formed, the conduction state control mechanism is controlled such that the pressure increase gradient of the non-ABS target wheel is suppressed. Therefore, despite the excessive capacity of the assist pressure generation means, the wheel P / JP97 / 02509 The pressure increase gradient of the damper pressure is suppressed to the appropriate gradient similar to when the BA control is executed alone.

Therefore, according to the above-described invention, when the BA control is being executed simultaneously with the ABS control, it is possible to prevent an excessive pressure increase gradient from occurring in the wheel cylinder pressure of the ABS non-target wheels.

According to another aspect of the present invention, a brake assist control that generates a larger brake hydraulic pressure than normal when an emergency brake operation is performed by a driver; The anti-braking brake control, which controls the pressure so as not to generate an excessive slip rate, and the braking force control device, which performs

Operating hydraulic pressure generating means for generating a brake hydraulic pressure according to the brake operation amount; a low pressure passage communicating with the first low pressure source and the second low pressure source;

Assist pressure generating means for generating a predetermined brake fluid pressure irrespective of a brake operation amount by pumping brake fluid sucked from the low pressure passage;

A conduction state control mechanism for controlling a conduction state between the wheel cylinder of each wheel and the high-pressure passage, and a conduction state between the wheel cylinder of each wheel and the low-pressure passage;

When an emergency brake operation is performed by a driver, the operating hydraulic pressure cut-off mechanism is shut off, and a predetermined brake hydraulic pressure is supplied from the assist pressure generating means to the high-pressure passage. ABS control means for controlling the wheel cylinder pressure of each wheel by controlling the BA control means and the conduction state control mechanism in a predetermined control pattern so that an excessive slip rate does not occur in each wheel. When,

The brake assist control and the anti-braking brake control are performed simultaneously. Low-pressure source power cut-off means for shutting off the first low-pressure source and the assist pressure generation means,

A braking force control device comprising:

In the above invention, when the driver performs an emergency brake operation, the BA control is started. During the execution of the BA control, the wheel cylinder pressure of each wheel is increased using the assist pressure generating means as a hydraulic pressure source. The assist pressure generating means sucks the brake fluid from the first low-pressure source and supplies the brake fluid pressure to the high-pressure passage when the BA control is performed by a single insect. In this case, a large amount of brake fluid is supplied to the high-pressure passage.

Β After the control is started, if an excessive slip rate is detected for any of the wheels, B A + ABS control is started. The ABS control is started when the wheel cylinder pressure of the -ABS target wheel is reduced, that is, the brake fluid is discharged from the wheel cylinder of the ABS target wheel to the low-pressure passage. Therefore, when the B A + A B S control is started, the brake fluid immediately flows into the second low pressure source.

In the present invention, when the BA + ABS control is started, the assist pressure generating means and the first low pressure source are shut off. Therefore, the brake fluid that can be pumped by the assist pressure generating means is limited to the brake fluid stored in the second low-pressure source thereafter. For this reason, unduly high brake fluid pressure does not occur in the high-pressure passage during the execution of the BA + ABS control. In a situation where unduly high brake fluid pressure is not generated in the high-pressure passage, the wheel cylinder pressure of the ABS target wheel does not increase excessively, and the wheel cylinder pressure F ' _{w /} There is no excessive pressure increase gradient in _C, and no excessive backflow of the brake fluid to the operating fluid pressure generation means.

Therefore, when the BA control and the ABS control are executed simultaneously, it is possible to prevent the generation of an unduly high brake fluid pressure in the high pressure passage. Wear.

Further, in the braking force control device according to the above-mentioned invention,

When the brake assist control and the anti-lock brake control are performed simultaneously and the wheel cylinder pressure is reduced at the target wheel for the anti-lock brake control, the operation hydraulic cut mechanism is turned on. It is also possible to provide a high-pressure passage opening means for setting the state.

When the B A + A B S control is being executed, the assist pressure generating means pumps only the brake fluid stored in the second low pressure source as described above. The brake fluid is discharged to the second low pressure source every time the wheel cylinder pressure of the ABS target wheel is reduced. For this reason, the assist pressure generating means sends a large amount of brake fluid to the high pressure passage in synchronization with the time when the wheel cylinder pressure is reduced at the ABS target wheel.

The high pressure passage is brought into conduction with the operating hydraulic pressure generating means only when a large amount of brake fluid is pumped by the assist pressure generating means. When the state of conduction between the high-pressure passage and the operating hydraulic pressure generating means is controlled as described above, the braking hydraulic pressure in the high-pressure passage becomes an appropriate pressure higher than the braking hydraulic pressure generated by the operating hydraulic pressure generating means. Controlled. Therefore, according to the present invention, the wheel cylinder pressure of the non-ABS target wheel can be increased with an appropriate pressure increase gradient without causing control hunting on the ABS target wheel.

Therefore, when the BA control and the ABS control are executed simultaneously, it is possible to prevent the occurrence of control hunting on the ABS target wheel, and the wheel cylinder pressure of the non-ABS target wheel has an excessive pressure increase gradient. Can be prevented.

Further, according to still another aspect of the present invention, a brake assist control for generating a larger brake oil pressure than usual when an emergency brake operation is performed by a driver, Excessive excess The anti-lack brake control that controls to a pressure that does not generate a rip ratio, and the braking force control device that executes

A low-pressure passage communicating with a predetermined low-pressure source;

A conduction state control mechanism for controlling a conduction state between the wheel cylinder of each wheel and the high pressure passage, and a conduction state between the wheel cylinder of each wheel and the low pressure passage;

BA control means for shutting off the operating hydraulic pressure cut-off mechanism when an emergency brake operation is performed by a driver, and for supplying predetermined brake hydraulic pressure to the high-pressure passage from the assist pressure generating means; An ABS control means for controlling the wheel cylinder pressure of each wheel by controlling the conduction state control mechanism according to a predetermined control pattern so that an excessive slip rate does not occur in each wheel;

A high-pressure passage opening unit that brings the operation hydraulic cut mechanism into a conductive state when the brake assist control and the anti-braking brake control are simultaneously performed;

A braking force control device comprising:

In the above invention, during execution of the BA + ABS control, the discharge capacity of the assist pressure generating means becomes excessive due to the fact that the wheel cylinder of the ABS target wheel is substantially disconnected from the high pressure passage. At this time, in the present invention, the high-pressure passage and the operating hydraulic pressure generating means are brought into conduction. When the high-pressure passage and the operating fluid pressure generating means are brought into conduction, the brake fluid discharged by the assist pressure generating means changes the operating fluid pressure. It is possible to flow into the pressure generating means. Therefore, even if the discharge capacity of the assist pressure generating means is excessive, an unduly high brake fluid pressure is not generated in the high pressure passage.

Therefore, when the BA control and the ABS control are performed simultaneously, it is possible to prevent the generation of an unduly high brake fluid pressure in the high-pressure passage.

Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a system configuration diagram of a braking force control device according to first to third embodiments of the present invention.

FIG. 2 is a graph showing a change in wheel cylinder pressure P w / c realized when the braking force control device shown in FIG. 1 executes ABS control. FIG. 3 is a graph showing a boost characteristic realized when a hydraulic pressure source is connected to the foil cylinder provided in the braking force control device shown in FIG. FIG. 4 is a graph showing the pressure increase gradient of the rear wheel wheel cylinder included in the braking force control device shown in FIG. 1 under various conditions.

FIG. 5 is a graph for explaining an overshoot of the wheel cylinder pressure realized in the braking force control device shown in FIG.

FIG. 6 is a flowchart of a control routine executed in the braking force control device according to the first embodiment of the present invention.

FIG. 7 is a graph showing a change in wheel cylinder pressure realized when the control routine shown in FIG. 6 is executed in the braking force control device according to the first embodiment of the present invention.

FIG. 8 is a flowchart of a control routine executed in the braking force control device according to the second embodiment of the present invention.

FIG. 9 shows the wheel cylinder pressure realized when the control routine shown in FIG. 8 is executed in the braking force control device according to the second embodiment of the present invention. 6 is a graph showing a change in the graph.

FIG. 10 is a diagram showing changes in the hydraulic pressure source and the pressure increase characteristics due to the execution and stop of the BA control.

FIG. 11 is a flowchart of a control routine executed in the braking force control device according to the third embodiment of the present invention.

FIG. 12 is a system configuration diagram showing a normal brake state and an ABS operation state of the braking force control device according to the fourth embodiment of the present invention. FIG. 13 is a diagram showing an assist pressure increasing state realized during BA control in the braking force control device shown in FIG.

FIG. 14 is a diagram showing an assist pressure holding state realized during BA control in the braking force control device shown in FIG.

FIG. 15 is a diagram showing a reduced assist pressure state realized during BA control or BA + ABS control in the braking force control device shown in FIG.

FIG. 16 is a diagram showing an assist pressure increasing state realized during BA + ABS control in the braking force control device shown in FIG.

FIG. 17 is a diagram showing an assist pressure holding state realized during BA + ABS control in the braking force control device shown in FIG.

FIG. 18 is a flowchart of a control routine executed to control the state of the reservoir cut solenoid in the braking force control device shown in FIG.

FIG. 19 is a flowchart of a control routine executed for selecting a control method of the holding solenoid and the pressure reducing solenoid in the braking force control device shown in FIG.

FIG. 20 is a flowchart of a control routine executed to realize the ABS control in the braking force control device shown in FIG. FIG. 21 is a flowchart of a control routine executed in the braking force control device shown in FIG. 12 to control the state of the mass cut solenoid. FIG. 22 is a system configuration diagram showing a normal brake state and an ABS operation state of the braking force control device according to the fifth embodiment of the present invention. FIG. 23 is a diagram showing an assist pressure increasing state realized during BA control in the braking force control device shown in FIG. 22.

FIG. 24 is a diagram showing an assist pressure holding state realized during BA control in the braking force control device shown in FIG.

FIG. 25 is a diagram showing a reduced assist pressure state realized during BA control or BA + ABS control in the braking force control device shown in FIG. 22.

FIG. 26 is a diagram showing an assist pressure increasing state realized during B A + ABS control in the braking force control device shown in FIG. 22.

FIG. 27 is a diagram showing an assist pressure holding state realized during B A + ABS control in the braking force control device shown in FIG. BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a system configuration diagram of a braking force control device according to a first embodiment of the present invention. The braking force control device shown in FIG. 1 is controlled by an electronic control unit 20 (hereinafter referred to as ECU 20). The braking force control device includes a pump 21. The pump 21 has a motor 22 as its power source. The suction port 21 a of the pump 21 communicates with the reservoir tank 23. An accumulator 25 communicates with a discharge port 21 b of the pump 21 via a check valve 24. The pump 21 pumps the brake fluid in the reservoir tank 23 from its discharge port 21 b so that a predetermined hydraulic pressure is always accumulated in the accumulator 25.

The accumulator 25 communicates with a high-pressure port 27 a of a regulator 27 and a regulator switching solenoid 28 (hereinafter referred to as STR 28) via a high-pressure passage 26. The regulator 27 is a low-pressure port 2 communicating with the reservoir tank 23 via a low-pressure passage 29. 7b, and a control hydraulic pressure port 27c communicating with the STR 28 via the control hydraulic pressure passage 30. The STR 28 is a two-position solenoid valve that selectively makes one of the control hydraulic passage 30 and the high-pressure passage 26 conductive, and in a normal state, makes the control hydraulic passage 30 conductive, In addition, the high-pressure circuit 26 is shut off. Here, the two-position solenoid valve means a solenoid valve that can be switched between two states.

The brake pedal 31 is connected to the regiré night 27, and the mass cylinder 32 is fixed. The Regyuyle 27 has a hydraulic chamber inside. The hydraulic chamber is always in communication with the control hydraulic port 27c, and is selectively connected to the high pressure port 27a or the low pressure port 27b depending on the operation state of the brake pedal 31. It is communicated. Regiyure Isseki 2 7, the internal pressure of the hydraulic chamber is configured to be adjusted to the hydraulic pressure corresponding to the brake pressing force F _P exerted on the brake pedal 3 1. Therefore, the control fluid pressure port 2 7 c of Regiyure Isseki 2 7 always hydraulic pressure appears corresponding to the brake pressing force F _P. Hereinafter, this fluid pressure is referred to as a regular pressure PRE.

Brake pressing force F _P exerted on the brake pedal 3 1 is mechanically transmitted to the master cylinder 3 2 via the Regiyure one evening 2 7. Further, the mass evening silicon Sunda 3 2, according to the hydraulic pressure of Regiyure Isseki 2 7 hydraulic chambers, i.e. Regiyure Isseki force corresponding to the pressure P _RE is transmitted. Hereinafter, this force is referred to as the brake assist force F _A. Therefore, when the brake pedal 31 is depressed, the mass cylinder 32 shows the brake depression force F

The resultant force of P and brake assist force F _A is transmitted.

The mass cylinder 32 has a first hydraulic chamber 32a and a second hydraulic chamber 32b therein. The first fluid pressure chamber 3 2 a and the second fluid pressure chamber 3 2 b, the master serial Nda圧P _{M / C} was depending on the resultant force of the brake pressing force F _P and a brake assist force F _a is generated. The mass cylinder pressure P _M / _C generated in the first hydraulic chamber 32 a and the mass cylinder pressure p _{M / c} generated in the second hydraulic chamber 32 _b are both provided by the provisional valve 3. 4 (after Below, it is called P valve 34).

The first hydraulic passage 36 and the second hydraulic passage 38 communicate with the P valve 34. P valve 3 4, in the area where the master serial Nda圧P _M / _C is less than a predetermined value, and against the first fluid pressure passage 3 6 and the second liquid pressure passage 3 8, the master serial Nda圧P _M / c Supply as is. Further, the P valve 34 supplies the mass cylinder pressure P _M / c to the first hydraulic passage 36 as it is in a region where the mass cylinder pressure P _{M / C} exceeds a predetermined value. At the same time, the master cylinder pressure P _M / c is supplied to the second hydraulic passage 38 at a predetermined ratio.

The second fluid pressure passage 3 8, fluid pressure sensor 4 0 for outputting an electrical signal proportional to the master serial Nda圧P _M / _C is being Ka設. The output signal of the hydraulic pressure sensor 40 is supplied to the ECU 20. The ECU 20 detects the master cylinder pressure PM _{/ C} generated in the master cylinder 32 based on the output signal of the hydraulic sensor 40.

The third hydraulic passage 42 communicates with the STR 28 described above. The third hydraulic passage 42 is in communication with one of the control hydraulic passage 30 and the high-pressure passage 26 according to the state of the STR 28. In the present embodiment, the wheel cylinders 44 FL, 44 FR arranged on the left and right front wheels FL, FR are connected to the first hydraulic pressure passage 36 communicating with the P valve 34 or the STR 28. The brake fluid pressure is supplied from the third fluid pressure passage 42. In addition, the wheel cylinders 44 RL, 44 RR disposed on the left and right rear wheels RL, RR are connected to the second hydraulic pressure passage 38 communicating with the P valve 34 or the STR 28. The brake fluid pressure is supplied from the third fluid pressure passage 42. The first hydraulic passage 36 has a first assist solenoid 46 (hereinafter referred to as SA- 46) and a second assist solenoid 48 (hereinafter SA-2448). ) Are in communication. On the other hand, the third hydraulic passage 42 includes a right front wheel holding solenoid 50 (hereinafter, referred to as SFRH 50), a left front wheel holding solenoid 52 (hereinafter, referred to as SF LH 52), and third § cis Totsurenoi de 5 4 (hereinafter, SA - ₃ referred to 5 4) is communicated with Here, in this specification, the solenoid means a solenoid valve.

SFRH50 is a two-position solenoid valve that normally keeps the valve open. The SFRH 50 communicates with the SAs 1, 46 and the right front wheel decompression solenoid 58 (hereinafter, referred to as S FRR 58) through a pressure adjusting hydraulic passage 56. A check valve 60 between the third hydraulic passage 42 and the pressure regulating hydraulic passage 56 allows only the flow of fluid from the pressure regulating hydraulic passage 56 to the third passage 42. Are juxtaposed.

S A- and 46 are two-position solenoid valves that selectively connect one of the second hydraulic passage 36 and the pressure regulating hydraulic passage 56 to the foil cylinder 44 FR, and are in a normal state (off state). In), the first hydraulic passage 36 and the foil cylinder 44 FR are brought into conduction. On the other hand, the SF RR 58 is a two-position solenoid on-off valve for bringing the pressure regulating hydraulic passage 56 and the reservoir tank 23 into a conductive state or a cutoff state. SF RR 58 shuts off the pressure regulating hydraulic passage 56 and reservoir tank 23 in the normal state (off state) _c SF LH 52 maintains the valve open state in the normal state 2-position electromagnetic It is an on-off valve. SF LH 5 2 via a pressure adjusting fluid pressure passage 6 2, SA - ₂ 4 8 and the left front wheel pressure-reducing source Renoi de 6 4 communicates with (hereinafter to referred as SFLR 6 4). A check valve 6 6 between the third hydraulic passage 42 and the pressure regulating hydraulic passage 62 allows only the flow of fluid from the pressure regulating hydraulic passage 62 to the third passage 42. Are juxtaposed.

SA - ₂ 4 8 has a first liquid hand of pressure passage 3 6 and the pressure adjusting fluid pressure passage 6 2, a position solenoid valve which selectively conducts to the wheel cylinders 4 4 FL, normal state (OFF state In), the i-th hydraulic passage 36 and the foil cylinder 44 FL are brought into conduction. On the other hand, the SF LR 64 is a two-position solenoid on-off valve that connects or disconnects the pressure regulating hydraulic pressure passage 62 and the reservoir tank 23. In the normal state (off state), the SFLR 64 keeps the pressure regulating hydraulic passage 62 and the reservoir tank 23 closed. The second fluid pressure passage 3 8, SA described above - is communicated with the ₃ 5 4. Downstream of SA-a54, right rear wheel holding solenoid 68 (hereinafter referred to as SRRH68) provided corresponding to wheel cylinder 44RR of right rear wheel RR, and A left rear wheel holding solenoid 70 (hereinafter, SR LR 70) provided corresponding to the wheel cylinder 44 RL of the left rear wheel RL is in communication. SA - ₃ 5 4 is one of the second fluid pressure passage 3 8 and a third fluid pressure passage 4 2, two-position which selectively communicates with the SR RH 6 8 Oyobi 3 shaku to 1¾ 7 0 solenoid The valve is in a normal state (off state), and the second hydraulic passage 38 communicates with the SRRH 68 and SRLR 70.

The wheel cylinder 44 RR and the right rear wheel decompression solenoid 74 (hereinafter referred to as S RRR 74) communicate with the downstream side of the SRRH 68 via a pressure adjustment hydraulic passage 72. ing. S RR R 74 is a two-position solenoid on-off valve that connects or disconnects the pressure regulating hydraulic passage 72 and the reservoir tank 23, and in a normal state (off state), the hydraulic pressure regulating passage is closed. The road 72 and the reservoir tank 23 are shut off. Further, a check valve 7 which allows only the flow of fluid toward the S A- 35 4 side from, the pressure adjusting fluid pressure passage 7 2 side between the S A- ₃ 5 4 Doo pressure adjusting fluid pressure passage 7 2 6 are juxtaposed.

Similarly, on the downstream side of the SR LH 70, a wheel cylinder 44 RL and a left rear wheel decompression solenoid 80 (hereinafter referred to as SRLR 80) are provided via a pressure regulating hydraulic passage 78. Communication). SR LR 80 is a two-position solenoid on-off valve that connects or disconnects the pressure-regulating fluid passage 78 and the reservoir tank 23. In the normal state (off state), the pressure regulating fluid passage 7 is opened. 8 and reservoir tanks 23 are shut off. Further, a check valve 82 which allows only the flow of fluid directed from the pressure adjusting fluid pressure passage 7 8 side to the SA - ₃ 5 4 side between S A- 35 4 Doo pressure adjusting fluid pressure passage 7 8 Are juxtaposed.

In the system of the present embodiment, a play switch 8 is arranged near the brake pedal 31. The brake switch 8 4 This switch generates ON output when the brake pedal 3i is depressed. The output signal of the brake switch 84 is supplied to the ECU 20. The ECU 20 determines whether or not the driver has performed a braking operation based on the output signal of the brake switch 84.

Further, in the system of this embodiment, wheel speed sensors 8 6 FL, 8 6 are provided near the left and right front wheels FL, FR and the left and right rear wheels RL, RR each time each wheel rotates a predetermined rotation angle. FR, 86 RL, 86 RR (hereinafter, collectively referred to with reference numeral 86 **) are provided. The output signal of the wheel speed sensor 86 ** is supplied to ECU20. ECU 20 detects the rotation speed of each wheel FL, FR, RL, RR, that is, the wheel speed of each wheel FL, FR, RL, RR, based on the output signal of wheel speed sensor 86.

Based on the output signals of the hydraulic pressure sensor 40, the wheel speed sensor 86 **, and the brake switch 84, the ECU 20 calculates the STR 28, SA, 46, SA- ₂ 48, _{SA- 3 5 4, SF RH 5} 0, SFLH 5 2, SFRR 5 8, SF LR 6 4, S RRH 6 8, SR LH 7 0, SRRR 7 4, and, as appropriate driving signal to the SRLR 8 0 Supply.

Next, the operation of the braking force control device according to the present embodiment will be described. Braking force control apparatus of the present embodiment, when the vehicle state is stable, executes normal control for generating a braking force corresponding to the brake pressing force F _P exerted on the brake Bae Da Le 3 1. Normal control, as shown in FIG. 1, STR 2 8, SA, 4 6, SA- 2 4 8, SA- 3 5 4, SF RH 5 0, SF LH 5 2, S FRR 5 8, SF LR 6 4 , SRRH 68, SRLH 70. This is realized by turning off all SR RR 74 and SR LR 80.

That is, in the state shown in FIG. 1, the foil cylinders 44 FR and 44 FL are placed in the first hydraulic passage 36 and the foil cylinder 44 4 RR and 44RL are communicated with the second hydraulic passage 38, respectively. In this case, the brake fluid is represented by the master cylinder 32 and the wheel cylinders 44 FR, 44 FL, 44 RL, and 44 RR (hereinafter, these are collectively denoted by reference numeral 44 **. ) Ri Do and be exchanged between the respective wheels FL, FR, RL, in RR, braking force corresponding to the brake pressing force F _P is generated.

In this embodiment, when it is detected that there is a possibility that any of the wheels may shift to the lip-lock state, the execution condition of the anti-lip brake control (hereinafter, referred to as ABS control) for the wheel is changed. It is determined that the condition has been established, and thereafter, the ABS control is started. ECU 20 calculates the wheel speed of each wheel Vw _F or Vw based on the output signal of the wheel speed sensor 8 6 **.

FR, VW RL, and VWRR (hereinafter collectively referred to by the symbol VW *) are calculated, and based on those wheel speeds Vw **, the estimated value V _s . (Hereinafter referred to as the estimated vehicle speed V _s ). Then, when the vehicle is in the braking state, the slip ratio S of each wheel is calculated according to the following equation, and when S exceeds a predetermined value, the wheel can shift to the licking state. Judge that

S = (V _S o-Vw »») 100 / Vso (1)

If the ECU 20 determines that the execution condition of the ABS control is satisfied for the right front wheel FR, the ECU 20 outputs a freewheel signal to SA-, 46. When the ECU 20 determines that the execution condition of the ABS control is satisfied for the left front wheel FR, the ECU ₂₀ outputs a drive signal to SA-248. When the ECU 20 determines that the execution condition of the ABS control is satisfied for any of the left and right rear wheels RL and RR, the ECU 20 outputs a drive signal to the SA-354.

When SA-, 46 are turned on, the foil cylinder 44 F is cut off from the first hydraulic passage 36 and communicated with the pressure adjusting hydraulic passage 56. Further, when SA_ ₂ 4 8 is turned on, the wheel cylinder 4 4 FL PT / JP97 / 02509 is shut off from the first hydraulic passage 36 and communicates with the pressure adjusting hydraulic passage 62. Moreover, SA - ₃ 5 4 is when it is turned on, S RRH 6 8 and SR LH 7 0 is communicated to the third fluid pressure passage 4 2 is blocked from the second fluid pressure passage 3 8.

As described above SA-, 4 6, S A- ₂ when 4 8 and SA - ₃ 5 4 is turned on, Hoirushiri Sunda 4 4 ** are, corresponding retention Sorenoi de SF RH 5 0, SF LH 5 2, S RRH 68, SR LH 70 (hereinafter collectively referred to as holding solenoid S ** H) and corresponding decompression solenoid SF RR 58, SFLR 64, S RRR 7 4, SRLR 80 (hereinafter collectively referred to as depressurizing solenoids S *, R), and the holding hydraulic fluid S ** H are connected to the third hydraulic passages 42 and through S TR 2 8, regulation Yu圧P _RE Gashirube Charles state is formed.

Under the above conditions, when the holding solenoid S ** H is opened and the pressure reducing solenoid S ** R is closed, the wheel cylinder pressure of the corresponding wheel cylinder 44 ** is set. Pw / c is increased with the regulation evening pressure P _Re as the upper limit. Hereinafter, this state is referred to as a pressure increase mode. In addition, when the holding solenoid S ** H is closed and the pressure reducing solenoid S ** R is closed under the above-described conditions, the foil cylinder of the corresponding foil cylinder 44 ** is closed. The pressure P _W / _C is maintained without increasing or decreasing. Hereinafter, this state is referred to as “② holding mode”. Further, when the holding solenoid S ** H is closed and the decompression solenoid S ** R is opened under the above conditions, the corresponding foil cylinder 44 " The pressure P _{w / C} is reduced, which is referred to as ③ pressure reduction mode.

The ECU 20 appropriately controls the pressure increase mode and the pressure retention mode as described above so that the slip ratio S of each wheel during braking falls within an appropriate value, that is, so that each wheel does not shift to the locked state. Mode and ③ decompression mode. Figure 2 shows that ECU 20 combines these modes. The time-dependent change of the wheel cylinder pressure P w / c realized when executing the ABS control is shown.

Figure 2 shows time t. Shows the case where the brake operation is started at time t1 and the execution condition of the ABS control is satisfied at time t1. Time t. After that, when the wheel cylinder pressure P _{w / C} rises and the slip ratio S of the wheel reaches a predetermined value at time and, the ABS control is started. In the following description, the wheel cylinder pressure c when the slip ratio S of the wheel reaches a predetermined value is referred to as the ABS hydraulic pressure.

When the execution condition of the ABS control is satisfied, first, the pressure reducing mode is realized in order to reduce the wheel cylinder pressure P _W / c from the ABS operating oil pressure. The time during which the decompression mode is maintained after the ABS control execution condition is satisfied (hereinafter, referred to as the first decompression time) is determined according to the slip state of the wheel when the ABS control execution condition is satisfied. Specifically, if the slip rate of the wheel is increasing slowly, the initial decompression time is set relatively short, while if the slip rate of the wheel is increasing rapidly, the initial decompression time is set. Is set to a relatively long time.

Figure 2 shows a case where decompression mode initial is maintained until time t _2. After the time to maintain the first decompression mode elapses, ③ hold mode is realized. Thereafter, a predetermined time should maintain retention mode elapsed Then, at time t ₃ is ① pressure increasing mode is started. After the pressure increase mode is maintained for a predetermined time, the time t ₄ Yuruzo圧mode (hereinafter, expressed subjected ④) is started. The gradual pressure increase mode is a mode realized by alternately executing ① pressure increase mode and ③ hold mode. Thereafter, when the wheel cylinder pressure P w / c reaches the ABS operating pressure again, the above-described series of control is performed again, ie, (2) pressure reduction mode— (3) hold mode → (1) pressure increase mode— (4) pressure increase mode. Processes to be realized sequentially are executed.

During the execution of the ABS control, (2) during the period in which the pressure reduction mode is executed, (3) during the period in which the hold mode is executed, and (4) most of the period in which the slow pressure increase is executed, 4 4 ** The corresponding holding solenoid S ** H shuts off the hydraulic pressure source (master cylinder 32 and the regulator 27). In this way, the foil cylinder to be subjected to the ABS control is substantially disconnected from the hydraulic pressure source during the execution of the ABS control.

After the driver depresses the brake pedal 31 during the execution of the ABS control, the wheel cylinder pressure P _{w / C} needs to be reduced immediately. In the system of the present embodiment, in the hydraulic path corresponding to each of the foil cylinders 44 **, there is a check that allows the flow of fluid from the foil cylinder 44 ** side to the third hydraulic passage 42 side. Valves 60, 66, 76, 82 are provided. For this reason, according to the system of the present embodiment, the wheel cylinder pressure P w / c of all the wheel cylinders 44 ** can be immediately reduced after the depression of the brake pedal 31 is released. .

When the ABS control is executed in the system of the present embodiment, the wheel cylinder pressure P _{w / C} is increased by the brake fluid being supplied from the regulator 27 to the wheel cylinder 44. That is, the pressure is increased by the brake fluid being supplied from the pump 21 to the wheel cylinders 44,. Further, the wheel cylinder pressure P w / c is reduced by the brake fluid in the wheel cylinder 44 ”flowing out to the reservoir 23. The increase in the wheel cylinder pressure P w / c is Assuming that the master cylinder 32 is used as a hydraulic pressure source, if the pressure increase mode and the pressure reduction mode are repeatedly performed, the brake fluid in the master cylinder 32 gradually decreases, In some cases, so-called mass cylinders may be attached to the floor.

On the other hand, if the foil cylinder pressure Pw / c is increased by using the pump 21 as a hydraulic pressure source as in the system of the present embodiment, such flooring can be prevented. Therefore, according to the system of the present embodiment, a stable operation state can be maintained even when the ABS control is continued for a long time. CT / P97 / 02509 By the way, in the system of the present embodiment, the ABS control is started when the possibility of shifting to the whipping state is detected for any of the wheels. Therefore, in order to start the ABS control, it is necessary to perform a braking operation to such an extent that a large slip ratio S occurs on any of the wheels as a prerequisite.

If the driver of the vehicle is advanced, after the situation in which an emergency braking is Ru is the need arises, immediately to soar brake pressing force F _P, and it is possible to maintain a large brake pressing force FP over a long period of time . If action is applied the brake pressing force F _P against the brake pedal 3 1, it can supply the brake fluid pressure sufficiently high pressure to each Hoirushiri Sunda 4 4 master serial Sunda 3 2, to start the ABS control be able to.

However, if the driver of the vehicle is a beginner, after situation the emergency brake is a need arises, there is a case where the brake pressing force F _P is not increased to a sufficiently large value. If the brake pedal force F _P acting on the brake pedal 31 is not sufficiently increased after the emergency braking is required, the wheel cylinder pressure P w / c of each wheel cylinder 44 * * is sufficiently increased. The ABS control may not be started.

Thus, if the driver of the vehicle is a beginner, even though the vehicle has an excellent braking capability, the capability may not be fully exerted even during an emergency braking operation. Therefore, Oite to the system of the present embodiment, the brake pedal 3 1 is operated with the intention of emergency braking, and, when the brake pressing force F _P is not sufficiently increased, forcing Ho Irushiri Nda圧P w / Control to boost c is executed. Hereinafter, this control is referred to as brake assist control (BA control).

In the system according to the present embodiment, when the brake pedal force FP is applied to the brake pedal 31, the brake pedal force F _P is applied to the master cylinder 32.

The master cylinder pressure PM / C corresponding to P is generated. When a normal braking operation is performed When a braking operation intended for emergency braking is performed The master cylinder pressure P _{M / C} changes more slowly compared to. Also, the master cylinder pressure P _{M / C} generated by the normal braking operation has a lower convergence value than the master cylinder pressure P _{M / C} generated by the braking operation intended for emergency braking.

For this reason, after the braking operation is started, the mass cylinder pressure P _{M / C} detected by the fluid pressure sensor 40 is increased to a sufficiently large value at a rate of change exceeding a predetermined value and a sufficiently large value. In this case, it can be determined that the braking operation intended for emergency braking has been performed. Also, when the master cylinder pressure ΡΜ / C shows a smaller change rate than the predetermined value after the braking operation is started, and when the convergence value of the master cylinder pressure PM _{/ C} does not reach the predetermined value. However, it can be determined that a braking operation intended for normal braking has been performed.

In the present embodiment, the mass cylinder pressure ΡΜ / C (hereinafter, the value is referred to as a detection value S PM / C), which is the detection value of the hydraulic pressure sensor 40, and the change rate ASP _M / _C thereof are When the predetermined emergency braking condition is satisfied and the detected value SP _{M / C} is not sufficiently increased (hereinafter, these conditions are collectively referred to as execution conditions of BA control). I have.

Hereinafter, the operation of the system according to the present embodiment accompanying the execution of the BA control will be described. When the driver performs a braking operation that satisfies the emergency braking condition, ECU 20 determines that the BA control execution condition has been satisfied. After determining that the BA control execution conditions are satisfied, the ECU 20 uses the accumulator 25 as the hydraulic pressure source, and the wheel cylinder pressure P _{W /} is higher than the master cylinder pressure PM _{/ C} as the hydraulic pressure source. It is determined whether or not a situation has been established that is advantageous for rapidly increasing _C. As a result, if a situation is formed in which it is more advantageous to use the accumulator 25 as the hydraulic pressure source, it is determined that the ECU 20 has reached the BA control start timing.

ECU 20 determines that the BA control start timing has arrived If, STR 2 8, S A- 4 6. SA -! 2 4 8 and SA - ₃ 5 4 with respect to output a driving signal. When the STR 28 is turned on in response to the drive signal, the third hydraulic passage 42 and the high-pressure passage 26 are directly connected. In this case, the accumulator pressure P _{ACC is} guided to the third hydraulic passage 42. Further, by receiving the drive signal S alpha-, 4 6 and SA - ₂ 4 8 When is O emissions state, Hoirushiri Sunda 4 4 FR and 4 4 FL, respectively pressure adjusting fluid pressure passage 5 6 and 6 2 Is communicated to. Furthermore, S A- ₃ 5 4 receives the drive signal is turned on, the upstream side of the SR RH 6 8 and SRLH 7 0 is communicated to the third fluid pressure passage 4 2. In this case, all the foil cylinders 44 "communicate with the respective holding solenoids S, * H and the respective decompression solenoids S ** R, and are upstream of all the holding solenoids S" H. And the accumulator pressure P

A state where ACC is led is formed.

If other braking force control such as ABS control is not being executed at the time when it is determined that the BA control start timing has arrived, all holding solenoids S ** H and all The decompression solenoid S ** R is kept off. Therefore, as described above, when the accumulator pressure P _ACC is led upstream of the holding solenoid S ** H, the fluid pressure is supplied to the foil cylinder 44 as it is. As a result, Hoirushiri Nda圧Pw / c of all Hoirushiri Sunda 4 4 ** is boosted towards the accumulator array Yu圧P _ACC.

As described above, according to the system of the present embodiment, when the emergency braking operation is performed, the wheel cylinder pressure P _{w / C of} all the wheel cylinders 44 ** is independent of the magnitude of the brake depression force FP. Can be rapidly increased. Therefore, according to the system of this embodiment, even if the driver is a beginner, a large braking force can be quickly generated after a situation in which emergency braking is required occurs.

When the BA control is started as described above by performing the emergency braking operation, when the depression of the brake pedal 31 is released, It is necessary to end BA control. Maintained in the system of the present embodiment, while the BA control is being executed, as described above S TR 2 8, S A-, 4 6, SA- 2 4 8, and SA - ₃ 5 4 within O emissions state Is done. STR 2 8, S A-, 4 6, SA- 2 4 8, and SA - ₃ 5 If 4 is in the on state, the first comprising Regiyure Isseki 2 7 inside the hydraulic chamber, and the master serial Sunda 3 2 And the second hydraulic chambers 32a and 32b are substantially closed spaces.

Under such circumstances, the master cylinder pressure P _{M / C} is a value corresponding to the brake depression force FP. Therefore, the ECU 20 monitors the output signal of the master cylinder pressure PM _{/ C} detected by the hydraulic pressure sensor 40 to easily determine whether or not the depression of the brake pedal 31 has been released. You can judge. When it detects the release of the brake pedal 3 1 of depression, ECU 2 0 is, S TR 2 8, SA-, 4 6, and stops supplying the drive signal to SA- ₂ 4 8, and S A- ₃ 5 4 To realize the normal control execution state. As described above, according to the system of the present embodiment, the BA control can be surely terminated with the termination of the braking operation. When the accumulator pressure P AC C starts to be supplied to the wheel cylinder 44 as described above, thereafter, the slip ratio S of each of the wheels FL, FR, RL, RR is rapidly increased, and the ABS control is eventually performed. The condition holds. When the execution condition of the ABS control is satisfied, the ECU 20 appropriately adjusts the slip rates S of all the wheels so as to be within an appropriate value, that is, so that each wheel does not shift to the licking state. Execute ABS control that combines (1) pressure increase mode, (2) hold mode, and (3) pressure reduction mode.

When the ABS control is executed after the BA control is started, the brake fluid is supplied from the pump 21 and the accumulator 25 to the wheel cylinder 44 by the wheel cylinder pressure P w / c. As a result, the brake fluid in the wheel cylinder 44 * flows into the reservoir tank 23, and the pressure is reduced. Therefore, Even if the pressure-increasing mode and the pressure-reducing mode are repeatedly performed, the so-called master cylinder 32 does not have a floor.

Next, the pressure increase gradient of the wheel cylinder pressure Pw / c realized by performing the BA control will be described. 3, pressure P. to time t ₅ Fig. 3 shows a pressure rise curve of the foil cylinder pressure P _{w / C} realized when the hydraulic pressure source for storing pressure is conducted to the foil cylinder 4 4 · ♦. Figure 3如rather than shown, Hoirushiri Nda圧P w / c of Hoirushiri Sunda 4 4 - *, after soaring after the time t _5, pressure P. while loosening the rate of increase Converges to At this time, the pressure increasing gradient dP / dt of the wheel cylinder pressure _PW / _C in the steep rising section is the pressure P. The pressure increases as the pressure increases, and as the hydraulic pressure storage amount of the hydraulic pressure source increases, that is, as the hydraulic pressure supply capacity of the hydraulic pressure source increases.

FIG. 4 shows the pressure increase gradient dB / dt of the wheel cylinder pressure P _{w / C} realized by the wheel cylinders 44 RL and 44 RR of the left and right rear wheels RL and RR. The broken line shown by the broken line in FIG. 4 represents the pressure increase gradient dB / dt realized when a sudden braking operation is performed during normal control. In addition, the broken line shown by a solid line, the broken line shown by a dashed line, and the broken line shown by a two-dot chain line in FIG. 4 indicate the BA control when ABS control is not performed for all foil cylinders 44, respectively. Pressure increase gradient dB / dt, which is realized when the control is started, the pressure increase gradient dB / dt, which is realized when the BA control is started under the condition that the ABS control is executed for one front wheel, The graph also shows the pressure increase gradient dB / dt realized when BA control is started under the condition that ABS control is being performed on two front wheels.

In the polygonal line shown in FIG. 4, the region where the slope is almost “0” corresponds to the region where the wheel cylinder pressure Pw / c is rapidly increased after the wheel cylinder pressure Pw / c starts to increase. I do. In the polygonal line shown in FIG. 4, the region having a negative slope indicates the region where the wheel cylinder pressure is high and the pressure is approaching and converging to the hydraulic pressure of the hydraulic pressure source. As shown in FIG. 4, the rear wheel cylinder pressure pulp _{/ c} shows a larger pressure increase gradient dB / dt during BA control than under normal control. Also, at the time of BA control, ABS control is performed by one front wheel before the BA control is started, compared to when ABS control is not performed for all wheel cylinders 44 *. When it is started, it shows a larger pressure increase gradient dB / dt. Further, when the ABS control is being performed on the front two wheels before the BA control is started, the increase is greater than when the ABS control is being performed on the front two wheels. Indicates the pressure gradient dB / dt.

As described above, the foil cylinder 44 **, which is to be controlled by the ABS control, is maintained in a state substantially separated from the hydraulic pressure source. Therefore, if ABS control is started for one wheel of the front when BA control is started, accumulator pressure P reaches the wheel cylinder of one wheel after BA control is started. do not do. In this case, after the BA control is started, the brake fluid flowing out of the accumulator 25 is a wheel cylinder 44 of the left and right rear wheels RL and RR, and a wheel cylinder 4 of the RL and RR and the front wheel 4 4 FL or 4 FL. 4 Supplied to FR only. Hereinafter, this case is referred to as a three-wheel pressure increase case. Also, if the ABS control has been started for the front two wheels at the time when the BA control is started, the accumulator pressure P _ACC reaches the wheel cylinder for the front two wheels after the BA control is started. do not do. In this case, the brake fluid flowing out of the accumulator 25 after the BA control is started is supplied only to the wheel cylinders 44 RL, RR of the left and right rear wheels RL, RR. Hereinafter, this case is referred to as a two-wheel pressure increase case.

After the BA control is started, the accumulator 25 stores brake fluid sufficient to quickly raise the pressure of the four wheel cylinders 44 ". If the brake fluid can flow into the foil cylinder 4 4 of the The pressure rises more rapidly in the wheel cylinders 44 ** of the left and right rear wheels RL and RR than in the case of a four-wheel pressure booster. Similarly, in the case of two-wheel pressure boosting, a more rapid pressure rise occurs in the wheel cylinders 44 of the left and right rear wheels RL and RR receiving the supply of brake fluid than in the case of three-wheel pressure boosting.

Figure 5 shows the change in the wheel cylinder pressure P _W / c realized in the rear wheel wheel cylinder 44 RL (same for 44 RR) as the two-wheel or three-wheel pressure is increased. Is shown. The change in the wheel cylinder pressure Pw / c shown in FIG. 5 indicates that the brake operation is started at time t _s , the BA control by the two-wheel or three-wheel pressure increase is started at time t 7, ₈ is realized when it is determined that the ABS cylinder execution condition is satisfied for the wheel cylinder 44RL.

As described above, when two-wheel or three-wheel pressure is increased by BA control, the wheel cylinder pressure Pw / c sharply increases in the wheel cylinder 44 RL compared to when four-wheel pressure is increased. Occurs. Therefore, such a case, after the establishment of the execution conditions of the AB S control is determined at time t _8, Hoirushiri Nda圧P _{w / C} phenomenon greatly exceed ABS braking hydraulic, i.e., Hoirushiri Nda圧Pw / Overshoot of c occurs.

As described above, E UC 10 sets the initial depressurization time to a relatively long time when the execution condition of the ABS control is satisfied and a sudden increase in the slip rate accompanies. Therefore, when an overshoot of the wheel cylinder pressure Pw / c occurs as shown in FIG. 5, immediately after the ABS control is started, the ECU 20 enters the decompression mode for a relatively long time. Execute.

If the decompression mode is maintained for a long time as described above, the wheel cylinder pressure Pw / c of the wheel cylinder 44 RL is transiently reduced to a small pressure, and the braking force generated by the rear wheel RL becomes an improperly small value. Sometimes. Thus, in the system shown in FIG. 1, the BA control is started. At this point, if ABS control has already been started on one of the front wheels or two of the front wheels, after the ABS control has been started on the rear wheels RL and RR following the BA control, then on the rear wheels RL and RR In some cases, a phenomenon in which the generated braking force is temporarily insufficient (hereinafter, this phenomenon is referred to as a G-drop phenomenon) may occur.

The braking force control device according to the present embodiment is characterized in that such a G drop phenomenon is prevented from occurring when the BS control is started. Incidentally, the above-described G-missing phenomenon can also occur when the ABS control is being performed on the rear wheels RL and RR at the time when the BA control is started. That is, if the ABS control is performed for one or two wheels at the rear before the BA control is started, the wheel cylinders 44 FL, FR of the front wheels FL, FR are simultaneously applied to the BA control when the BA control is started. In this case, an overshoot of the wheel cylinder pressure P _{w / C} occurs. If Shimese front wheels FL, Hoirushiri Nda圧P _{w / C} is over one sheet Yu bets FR like this, the AB S control is then started, the front wheel FL, is Hoirushiri Nda圧Pw / c of the FR is largely reduced pressure Will be. However, the wheel cylinders 44 FL, 44 FR of the front wheels FL, FR are given a larger capacity than the wheel cylinders 44 RL, 44 RR of the rear wheels RL, RR. For this reason, even if the ABS control of the rear wheels RL and RR is executed before the BA control, the wheel cylinder pressure Pw / c of the front wheels FL and FR may overshoot so much after the BA control is started. Absent. If the overshoot amount of the wheel cylinder pressure Pw / c is not so large, the wheel cylinder pressure Pw / c of the front wheels FL and FR is unduly greatly reduced by the ABS control started thereafter, that is, No large G dropouts occur. For this reason, in the present embodiment, the process for preventing the loss of G is executed only when the ABS control has been started for the front wheels FL and FR prior to the execution of the BA control.

Fig. 6 shows the control loop executed by the ECU 20 to realize the above functions. 3 shows a flowchart of the chin. The routine shown in FIG. 6 is a periodic interrupt routine that is started at predetermined time intervals. When this routine is started, the process of step 100 is executed.

In step 100, it is determined whether or not the BA control is being executed. The ECU 20 determines that the BA control is being executed when the STR 28 is in the ON state. This routine is for preventing the wheel cylinder pressure Pw / c of the rear wheels RL and RR from being overshot at the start of the BA control. Therefore, if the BA control has already been started, there is no benefit to proceed with the processing of this routine. Therefore, if the above determination is made, the current routine ends without any further processing. On the other hand, if it is determined in this step that the BA control is not being executed, that is, that the STR 28 is in the off state, then the process of step 102 is executed.

In step 102, it is determined whether or not the BA control start timing has arrived. As a result, if it is determined that the BA control start timing has not yet arrived, the routine is terminated without any further processing. On the other hand, if it is determined that the BA control start timing has arrived, the process of step 104 is performed next.

In step 104, it is determined whether or not the ABS control is being performed on at least one of the two front wheels. Specifically, whether one be a least one of S A- i 6 and S A- ₂ 4 8 it is a O emissions state is determined. If the above conditions are not satisfied, it can be determined that even if the BA control is started, the wheel cylinder pressure P _{w /} c of the rear wheels RL and RR does not unduly sharply increase. In this case, after the normal BA control is started in step 106, the current routine ends.

On the other hand, if it is determined in step 104 above that ABS control has been executed for at least one of the two front wheels, BA After the control is started, it can be determined that there is a possibility that the wheel cylinder pressure P _{w / C of} the rear wheels RL and RR is rapidly increased and unduly overshot. For this reason, when such a determination is made, an overshoot of the wheel cylinder pressure P _{w / c} of the rear wheels RL, RR should be prevented, and then the processing of step 108 is executed.

In step 108, the BA gradient suppression control is started. In the BA gradient suppression control, in addition to the processing to be executed for realizing the normal BA control, the wheel cylinders 44 of the rear wheels RL and RR, and the SRRH 60 and SR LH 70 communicating with the RL and RR are cycled for a predetermined period This is achieved by turning off the power. When the process for realizing the normal BA control is executed, the wheel cylinders 44 RL, RR of the rear wheels RL, RR and the accumulator 25 become conductive. If SRRH 60 and SR LH 70 are turned on and off periodically in such a situation, the accumulation 25 and the foil cylinders 44 RL and 44 RR are intermittently shut off. As a result, the amount of brake fluid flowing into the wheel cylinders 44RL and 44RR is suppressed. Therefore, according to the BA gradient dB / dt suppression control, it is possible to prevent the wheel cylinder pressure Pw / c of the rear wheels RL, RR from being unduly sharply increased. When the processing of step 108 is completed, the current routine is completed.

FIG. 7 shows a change in the wheel cylinder pressure P _{w / C} realized in the rear wheel foil cylinder 44 RL (the same applies to 44 RR) by performing the above processing. Note that the change in the wheel cylinder pressure P _{w / C} indicated by the one-dot chain line in FIG. 7 is the same as the characteristic diagram shown in FIG. 5 above, and the wheel cylinder pressure P _w realized when the BA gradient suppression control is not executed. _{Shows / C} change.

, The time t, after the ABS control is started change shown by the solid line, the brake operation at time t ₉ is started, at least the front one wheel in FIG. The BA gradient suppression control is started at time t, and at time t _n , it is determined that the execution condition of the ABS control for the foil cylinder 44RL is satisfied. Is realized when

As described above, according to the BA gradient suppression control, even if the ABS control is started for one or two front wheels at the time when the execution condition of the BA control is satisfied, the wheel cylinder pressure Pw of the rear wheels RL and RR is obtained. / c can be gradually increased. For this reason, when the BA gradient suppression control is executed, the wheel cylinder pressure P _{w / C} of the rear wheels RL, RR does not overshoot significantly exceeding the ABS operating oil pressure. Further, if occurs over one chute to Hoirushiri Nda圧P _{w / C,} the rear wheels RL, after the ABS control is started for the RR, that the wheel Siri Nda圧P _{w / C} is decreased excessively Absent. For this reason, according to the braking force control device of the present embodiment, if the execution condition of the BA control is satisfied after the ABS control is started for one or two wheels of the front, G escape occurs. Can be prevented. Therefore, according to the braking force control device of the present embodiment, good controllability can always be maintained.

In the above embodiment, the braking force control executed before the BA control is started is limited to the ABS control, but the present invention is not limited to this. That is, the present invention is also applicable to a case where another control hydraulic pressure reduction control for controlling the wheel cylinder pressure P _{w / C} in a state where the hydraulic pressure inflow path of the foil cylinder is shut off is used instead of the ABS control. Is possible.

Further, in the above embodiment, when the "front wheel FL, FR" ABS control is executed, the "back wheel RL, RR" BA gradient suppression control is executed, but the present invention is not limited to this. It is not limited. That is, if brake fluid pressure reduction control such as ABS control is being performed on any of the wheel cylinders, BA gradient suppression control should be performed on the other wheel cylinders. In the above embodiment, the hydraulic pressure control passages 56 and 62 correspond to the “hydraulic pressure inflow path”, and the ABS control corresponds to the “brake hydraulic pressure reduction control”. The ECU 20 executes the processing of the above step 104, and the continuity detecting means is performed. The ECU 20 executes the processing of the above step 108, so that the hydraulic pressure is detected. Inflow suppression means are realized respectively.

Next, a second embodiment of the present invention will be described with reference to FIGS. The braking force control device according to the present embodiment is realized by causing the ECU 20 to execute the routine shown in FIG. 8 instead of the routine shown in FIG. 6 in the system shown in FIG.

The braking force control device according to the first embodiment described above is configured such that, when the ABS control is performed on at least one front wheel before the execution condition of the BA control is satisfied, the wheel cylinder associated with the start of the BA control is controlled. Pressure

The overshoot of the wheel cylinder pressure Pw / c is suppressed by reducing the rate of increase of Pw / c. However, the BA control is a control executed for the purpose of quickly raising the wheel cylinder pressure Pw / c when an operation requesting an emergency brake is performed. In this regard, a technique of the first embodiment described above is employed, _c present embodiment are contradictory with BA control original purpose, one wheel of least front even prior to the execution conditions of the BA control is established The feature is that when the ABS control is started, the overshoot of the wheel cylinder pressure Pw _{/ C} is prevented without reducing the rate of increase of the wheel cylinder pressure Pw / c accompanying the start of the BA control. Have.

FIG. 8 shows a flowchart of an example of a routine executed by the ECU 20 to realize the above functions. This routine is a routine that is executed to determine when to start the ABS control for the rear wheels RL and RR. This routine is a periodic interrupt routine that is started every predetermined time. When this routine is started, the processing of step 110 is executed.

In step 110, it is determined whether the BA control is being performed. Specifically, it is determined whether or not STR 28 is on. You. As a result, when it is determined that STR 28 is in the off state, it is determined that BA control is not being performed. In this case, the process of step 120 is executed next.

In step 120, it is determined whether or not the slip amount of the rear wheels RL, RR is greater than a predetermined value Δν ,. Δν, is the slip amount immediately before the wheel goes into the locked state. If it is determined that the slip amount of the rear wheels RL, RR exceeds Δν, as a result of the above determination, it is determined that the ABS control should be started for the rear wheels RL, RR. In this case, the process of step 122 is executed next. On the other hand, if it is determined in step 120 that the slip amount of the rear wheels RL and RR is equal to or smaller than ΔV, it is determined that it is not necessary to start the ABS control, and the current processing ends. Is done.

In step 122, a process for starting the normal ABS control is executed. After the processing of this step 122 is executed, the above-described ABS control, that is, the processing of (2) depressurization mode— (3) hold mode (1) pressure increase mode— (4) repetition of the slow pressure increase mode starts. Is done. When the processing in step 122 is completed, the current routine is completed.

In the above step 110, if it is determined that the BA control is being executed, that is, if the STR 28 is in the ON state, then the processing of step 112 is executed. In step 1 1 2, whether the ABS control for at least one wheel of the front 2 wheels are running, i.e., S alpha-, 4 6 and SA - ₂ 4 8 least also for the one is turned on Is determined. As a result, if it is determined that the above condition is not satisfied, it is determined that the wheel cylinder pressure Pw / c of the rear wheels RL and RR has not undergone a sudden pressure increase different from the normal state due to the execution of the BA control. can do. In this case, next, the processing of step 120 is executed in order to determine the execution of the ABS control under normal conditions.

On the other hand, in step 1 1 and 2 above, at least one of the two front wheels If it is determined that the ABS control is being performed on the wheels, the wheel cylinder pressures P and c of the rear wheels RL and RR increase sharply as compared with normal times due to the execution of the BA control. It can be determined that. In this case, the process of step 114 is performed next.

In step 114, it is determined whether or not the slip amount of the rear wheels RL, RR is larger than a predetermined value Δν 2. Δν ₂ is a smaller value than the threshold value Δν, used in the above step 120, that is, a smaller value than the slip amount at which the wheel shifts to the licking state. Above results SL discrimination, the rear wheels RL, when the Slip amount of RR is determined to be .DELTA..nu ₂ or less, yet the rear wheels RL, Hoirushiri Nda圧P _{w /} c ratio to ABS hydraulic pressure of the RR C In this case, the current routine is terminated without any further processing.

On the other hand, in step 1 1 4, when the rear wheels RL, is Slip amount of RR is determined to exceed the厶V _2, the rear wheels RL, is Hoirushi Li Nda圧P _{w / C} of RR ABS It can be determined that the pressure has increased to near the working oil pressure. In this case, the processing of step 116 is executed next.

In step 116, it is determined whether or not the ABS control for the rear wheels RL, RR has already been started. If it is determined that the ABS control for the rear wheels RL and RR has not been started yet, the boosting characteristic of the wheel cylinder pressure Pw / c of the rear wheels RL and RR is controlled by the BA control. It can be determined that the pressure P _{w / C} is rapidly increased. In this case, the process of step 118 is executed next.

On the other hand, if it is determined in step 1 16 that the ABS control for the rear wheels RL and RR has already been started, the boost characteristic of the wheel cylinder pressure Pw / c of the rear wheels RL and RR is changed by the ABS control. Is dominated, that is, its foil cylinder pressure Pvv / c no longer You can judge that it is not. In this case, the process of step 120 is then performed to continue the normal ABS control.

In step 118, processing for starting the first specific ABS control is performed. In the first specified ABS control, the execution time of the decompression mode, which is executed immediately after the start of the ABS control, is longer than the execution time of the decompression mode, which is normally executed during the ABS control. Control. According to the first specified ABS control, the wheel cylinder pressure Pw / c of the rear wheels RL and RR can be greatly reduced as compared with the normal ABS control. When the process of step 1 18 is completed, the current routine is completed. According to the above processing, even if the ABS control has been started for at least one front wheel prior to the start of the BA control, the slip of the rear wheels RL and RR is started after the BA control is started. until flop weight obtain ultra the AV _2, the rear wheels RL, the Hoirushiri Nda圧P _{w / C} of the RR can be sharply boosted. Also, when the rapidly increased wheel cylinder pressure P _{w / C} is increased to a value close to the ABS operating oil pressure, the wheel cylinder pressure Pw / c of the rear wheels RL and RR is reduced by the first specific ABS control at that time. Can be started. Furthermore, according to the first specified ABS control, (2) the pressure reducing mode is maintained for a long time, so that the rapidly raised wheel cylinder pressure P _{w / C} can be reduced appropriately. Therefore, according to the braking force control device of the present embodiment, it is possible to reliably prevent the wheel cylinder pressure Pw / c of the rear wheels RL and RR from overshooting after the BA control is started.

FIG. 9 shows a change in the wheel cylinder pressure P _{w / C} realized in the rear wheel foil cylinder 44 RL (the same applies to 44 RR) by performing the above processing. Note that the change in the wheel cylinder pressure Pw / c indicated by the dashed line in FIG. 9 is similar to the characteristic diagram shown in FIG. 5 above when the normal BA control is started and then the normal ABS control is started. It shows the change in foil cylinder pressure P _{w / C} realized in this case.

Change shown by a solid line in FIG. 9, the braking operation is started at time t _12, After the ABS control is started for the front one wheel at least, is BA control starts at the time t _13, further time t _14, the execution condition of the first specific ABS control is established about Hoirushiri Sunda 4 RL, Sunawa Chi, Slip amount of the rear wheels RL is realized when it is determined to exceed the AV _2.

When the BA control is started with the ABS control started for at least one front wheel, thereafter, the wheel cylinder pressure P w / c of the rear wheel RL rapidly increases. On the other hand, according to the first specific ABS control, the wheel cylinder pressure Pw / _C of the wheel cylinder 44 RL can be reduced earlier and largely than in the case of the normal ABS control. For this reason, in the braking force control device of the present embodiment, an overshoot that greatly exceeds the ABS operating oil pressure does not occur in the wheel cylinder pressure P _{w / C} of the rear wheels RL and RR. For this reason, according to the braking force control device of the present embodiment, excellent controllability is maintained when the BA control execution condition is satisfied after the ABS control is started for one or two front wheels. can do.

In the above embodiment, the braking force control executed before the BA control is started is limited to the ABS control, but the present invention is not limited to this. That is, in the present invention, instead of the ABS control, first, the wheel cylinder pressure P _{w / C} is reduced in a state where the hydraulic pressure inflow path of the foil cylinder is shut off, and then another braking fluid for executing a desired hydraulic pressure control is performed. It is also applicable when pressure control is used.

Further, in the above-described embodiment, when the "front wheel FL, FR" ABS control is performed, the "rear wheel RL, RR" first specific ABS control is performed. It is not limited to. In other words, the present invention can be applied to a case where the brake fluid pressure control such as the ABS control is performed for any one of the wheel cylinders and the first specific ABS control is performed for the other wheel cylinder. In the above-described embodiment, the slip amount of the wheel corresponds to the “characteristic value relating to the slip state of the wheel”, and the hydraulic pressure control passages 56 and 62 correspond to the “hydraulic inflow path”. The control corresponds to the "braking fluid pressure control", the control for realizing the decompression mode for the first time during the ABS control corresponds to the "intimidation control", and the ECU 20 performs the processing of the above steps 112. By executing, the “conduction detecting means” is realized, and the ECU 20 executes the processing of the above step 118 to realize “threshold changing means” and “pressure reduction changing means”.

Next, a third embodiment of the present invention will be described with reference to FIG. 10 and FIG. The braking force control device according to the present embodiment is configured such that, in the system configuration shown in FIG. 1, the ECU 20 is replaced with the routine shown in FIG. 6 or FIG. 8 or the routine shown in FIG. 6 or FIG. This is realized by executing the control routine shown in FIG.

The pressure increase gradient of the wheel cylinder pressure P _W / c due to the execution of the ABS control is determined by the hydraulic pressure of the hydraulic pressure source that supplies the hydraulic pressure to the wheel cylinder 44 ”(that is, the regulator pressure P PRE or the accumulator pressure P _ACC). ) And the wheel cylinder pressure Pw / c, the effective diameter of the hydraulic passage and the solenoid valve, and the opening time of the holding solenoids S and * H, etc. In a system where BA control is not executed In this system, the characteristics of the hydraulic pressure source and the hydraulic passage do not change.In such a system, the contents of the ABS control are tuned on the assumption that those characteristics are fixed.

However, in a system in which the BA control is executed, the hydraulic pressure source and the hydraulic passage are changed with the execution of the BA control. For this reason, in such a system, a different pressure increasing gradient is given to the wheel cylinder pressure Pw / c depending on whether the ABS control is executed independently or when the ABS control is executed together with the BA control. . If the pressure increase gradient of the wheel cylinder pressure Pw / c changes due to the ABS control, the control characteristics of the ABS control change, and the same braking characteristics cannot always be obtained. By the way, even in a system in which the BA control is executed, if the content of the ABS control is switched according to whether or not the BA control is executed, the execution of the ABS control is performed regardless of whether the BA control is being executed. It is possible to obtain a similar pressure increase gradient inside. The braking force control device of the present embodiment is characterized in that the above functions are realized by changing the setting conditions of the ABS control according to the execution state of the BA control.

FIG. 10 shows changes in the hydraulic pressure source and the pressure increase characteristics due to the execution and stoppage of the BA control in the system shown in FIG. As shown in FIG. 10, while BA control is not being performed in the system of the present embodiment, the regulator 27 is a hydraulic pressure source during ABS control. At this time, in the system of the present embodiment, the hydraulic discharge capacity of the regulator 27, the characteristics of the passage connecting the regulator 27 to the third hydraulic passage 42, and the third hydraulic passage 4 (2) Pressure boosting characteristics according to the downstream characteristics (hereinafter, this pressure boosting characteristic is referred to as characteristic (2)) are realized.

As shown in FIG. 10, while the BA control is being performed in the system of the present embodiment, the accumulator 25 is a hydraulic pressure source during the ABS control. At this time, in the system of the present embodiment, the hydraulic discharge capacity of the pump 21 and the accumulator 25, the characteristics of the passage from the accumulator 25 to the third hydraulic passage 42, and the third hydraulic passage 4 (2) The pressure increasing characteristic according to the downstream characteristics (hereinafter, this pressure increasing characteristic is referred to as characteristic I) is realized.

FIG. 11 shows a flowchart of an example of a control routine executed by the ECU 20 so as to make the characteristics ① and ② identical. This routine is a periodic interrupt routine that is started every predetermined time. When this routine is started, first, the processing of step 130 is executed.

In step 130, it is determined whether the BA control is being executed. In step 130, the above determination is made based on the state of the STR 28. Specifically, when the STR 28 is in the off state, the BA control is not executed, and the STR 28 is in the on state. In this case, it is determined that the BA control is being executed. If it is determined that the BA control has not been performed, the process of step 1332 is performed next. On the other hand, if it is determined that the BA control is being performed, the process of step 13 is performed next.

In step 132, a process is performed with the driving condition of the ABS control as condition (2). The condition ① is a condition for setting the characteristic ① to a desired pressure increasing gradient in the case of communication with the third hydraulic passage 42 via the regulation hydraulic passage 30, the control hydraulic passage 30 and the STR 28. It is. When the processing of this step 13 is completed, the current routine is completed. After the processing of the above steps 1 32 is executed, the ABS control is thereafter executed according to the condition (2).

In step 134, a process is executed in which the driving condition of the ABS control is the condition (2). Condition ② is a condition for setting the characteristic とする to a desired pressure increasing gradient when communicating with the third hydraulic pressure passage 42 via the accumulator 25, the high-pressure passage 26, and the STR 28. is there. When the processing of the present step 1 34 is completed, the current routine is completed. After the processing of the above step 1 34 is executed, the ABS control is thereafter executed according to the condition (2).

According to the above processing, regardless of whether the BA control is being executed or not, the wheel cylinder pressure P w / c is always increased with the desired pressure increasing characteristic in accordance with the execution of the ABS control. Becomes possible. For this reason, according to the braking force control device of the present embodiment, it is possible to avoid the inconvenience that the controllability of the ABS control deteriorates with the execution of the BA control.

In the present embodiment, the driving pattern of the holding solenoid S ** H is determined by the conditions (1) and (2). More specifically, two types of maps that determine the driving pattern of the holding solenoid S ** H are prepared, and which of the maps is used under the conditions 1 and 2 is determined. The method of switching the driving pattern of the holding solenoid S ** H is not limited to this, but depends on whether or not to correct the reference map. Alternatively, the drive pattern may be switched.

Further, in the above embodiment, the contents to be determined by the conditions (1) and (2) are limited to the driving pattern of the holding solenoid S ** H. The present invention is not limited to this. For example, the same pressure increase gradient may be realized during execution of the BA control and during non-execution of the BA control by changing the characteristics of the hydraulic pressure source.

Next, a braking force control device according to a fourth embodiment of the present invention will be described with reference to FIGS.

1 2, the fourth exemplary pump-up type brake force control apparatus according to an example of the present invention (hereinafter, simply referred to as a brake force control apparatus) _c braking force control apparatus of the present embodiment showing a system configuration diagram of front This device is suitable as a braking force control device for engines and rear drive type vehicles (FR vehicles). The braking force control device of the present embodiment is controlled by an electronic control unit 210 (hereinafter, referred to as ECU 210).

The braking force control device includes a brake pedal 2 1 2. In the vicinity of the brake pedal 211, a brake switch 214 is provided. The brake switch 2 14 outputs an ON signal when the brake pedal 2 12 is depressed. The output signal of the brake switch 2 14 is supplied to the ECU 210. The ECU 210 determines whether or not the brake pedal 2 12 is depressed based on the output signal of the brake switch 2 14.

The brake pedal 2 12 is connected to the vacuum booster 2 16. The vacuum booster 216 is fixed to the master cylinder 218. When the brake pedal 2 12 is depressed, the vacuum booster 2 16 generates an assist force Fa having a predetermined boosting ratio with respect to the brake depression force F. The mass cylinder 218 is a conventional master cylinder of a central valve type, and has a first hydraulic chamber 220 and a second hydraulic chamber 222 inside thereof. The first hydraulic chamber 222 and the second hydraulic chamber 222 have the brake depression force F The master cylinder pressure P _{M / C} is generated according to the resultant force with the assist force Fa.o

A reservoir tank 224 is provided above the master cylinder 218. A front reservoir passage 226 and a reservoir reservoir 228 communicate with the reservoir tank 224. A front reservoir cut solenoid 230 (hereinafter referred to as SRCF 230) communicates with the front reservoir passage 226. Similarly, a reservoir reservoir solenoid 2 32 (hereinafter referred to as SRCR 232) communicates with the reservoir reservoir passage 228.

Further, a front pump passage 234 communicates with the SRCF 230. Similarly, a rear pump passage 236 communicates with the SRCR 232. The SRCF 230 shuts off the front reservoir passage 226 and the front pump passage 234 when turned off, and conducts them when turned on. It is a solenoid valve. The SRCR 232 is a two-position solenoid valve that shuts off the rear reservoir passage 228 and the rear pump passage 236 when turned off and conducts them when turned on. It is.

A first hydraulic passage 238 and a second hydraulic passage 240 communicate with the first hydraulic chamber 220 and the second hydraulic chamber 222 of the master cylinder 218, respectively. I have. The first hydraulic pressure passage 238 has a right front mass cutoff nozzle 242 (hereinafter referred to as SMF R 242) and a left front master cut solenoid 244 (hereinafter SMF L 224). 4). On the other hand, the second hydraulic passage 240 communicates with a rear mass cut solenoid 246 (hereinafter referred to as SMR 246).

The SMF R 242 communicates with a hydraulic passage 248 provided corresponding to the right front wheel FR. Similarly, a hydraulic passage 250 provided in correspondence with the left front wheel FL communicates with the SMF L 244. Further, the SMR 246 communicates with hydraulic passages 252 provided corresponding to the left and right rear wheels RL, RR. SMF R 244 2. Inside the SMF L 244 and SMR 246, constant pressure release valves 254, 258 and 258 are provided, respectively. The S MF R 242 makes the first hydraulic passage 238 and the hydraulic passage 248 conductive when turned off, and the constant pressure release valve 2 when turned on. This is a two-position solenoid valve that communicates the first hydraulic pressure passage 238 and the hydraulic pressure passage 248 via 54. In addition, the SMF L 242 puts the first hydraulic passage 238 and the hydraulic passage 250 in a conductive state when the state is turned off, and a constant pressure release valve when the state is turned on. This is a two-position solenoid valve that connects the first hydraulic passage 2 388 and the hydraulic passage 250 via the second and fifth hydraulic passages. Similarly, when the SMR 246 is turned off, the second hydraulic passage 240 and the hydraulic passage 252 are connected to each other, and when the SMR 246 is turned on, the constant pressure release valve 2 is connected. This is a two-position solenoid valve that communicates the second hydraulic passageway 240 and the hydraulic passageway 252 through 58.

Between the first hydraulic passage 238 and the hydraulic passage 248, only fluid flowing from the first hydraulic passage 238 to the hydraulic passage 248 is allowed. A check valve 260 is provided. Similarly, between the first hydraulic passage 238 and the hydraulic passage 250 and between the second hydraulic passage 240 and the hydraulic passage 252, the first hydraulic passage is provided. Check valve 2 62 that allows only fluid flow from passage 2 380 to hydraulic passage 250, and second hydraulic passage 240 to hydraulic passage 252 A check valve 26 4 is provided to allow only the flow of the fluid to flow.

A hydraulic passageway 248 corresponding to the right front wheel FR communicates with a right front wheel holding solenoid 2666 (hereinafter referred to as SF RH266). Similarly, the hydraulic passage 250 corresponding to the left front wheel FL has a left front wheel holding solenoid 268 (hereinafter referred to as SF LH 268). The hydraulic passages 25 2 have a right rear wheel holding solenoid 270 (hereinafter, S RRH 270) and a left rear wheel holding solenoid 272 (hereinafter, SRLH 272). Power, each communicates. Hereinafter, when these solenoids are collectively referred to, they will be referred to as “holding solenoid S ** H”. The right front wheel decompression solenoid 274 (hereinafter referred to as SFRR 274) communicates with the SF RH 266. Similarly, SFLH 268, SRRH 270 and SRLH 272 have left front wheel decompression solenoids 276 (hereinafter referred to as SF LR 276) and right rear wheel decompression solenoids 2 respectively. 780 (hereinafter referred to as SRRR 278) and left rear wheel decompression solenoid 280 (hereinafter referred to as SRLR 280) communicate with each other. Hereinafter, when these solenoids are collectively referred to as “decompression solenoid S ** R”.

The wheel cylinder 282 of the right front wheel FR communicates with the SFR H266. Similarly, the wheel cylinder 284 of the left front wheel FL is on the SFLH 268, the wheel cylinder 286 of the right rear wheel RR is on the SR RH270, and the left is the wheel cylinder 268 on the right rear wheel RR. The wheel cylinders 288 of the rear wheel RL communicate with each other.

Further, between the hydraulic passage 2 48 and the foil cylinder 28 2, the hydraulic passage 2 is bypassed from the foil cylinder 28 2 by bypassing the SFRH 266.

A check valve 290 is provided to allow fluid flow to 4.8. Similarly, between the hydraulic passage 250 and the foil cylinder 2884, between the hydraulic passage 25 and the foil cylinder 2886, and the hydraulic passage 2

Non-return valves 292, 2 permit flow of fluid that bypasses SFLH 268, SRRH 270 and SR LH 272, respectively, between 52 and foil cylinder 288. 9 4 and 2 9 6 are provided.

The SFRH 266 makes the hydraulic passage 248 and the foil cylinder 282 conductive when turned off, and the hydraulic passage 248 and the foil cylinder when turned on. This is a 2-position solenoid valve that shuts off 282. Similarly, SF LH 268 and S RRH 270 and 31 ¾ 1 ^^ 272 are respectively turned on so that the paths connecting the hydraulic pressure passage 250 and the wheel synthesizer 284 are formed. A two-position solenoid valve that shuts off the path connecting the hydraulic passageway 252 and the wheel cylinder 2886 and the path connecting the hydraulic passageway 252 and the wheel cylinder 2888 O

A front pressure reducing passageway 298 communicates with the pressure reducing solenoids SFR R274 and SFLR274 of the left and right front wheels. In addition, a rear decompression passageway 300 communicates with decompression solenoids SRRRR278 and SRLR280 of the left and right rear wheels. The front pressure reducing passageway 298 and the rear pressure reducing passageway 300 communicate with a front reservoir 302 and a rear reservoir 304, respectively.

In addition, the front pressure reducing passageway 298 and the rear pressure reducing passageway 300 are respectively connected to the suction side of the front pump 310 and the rear pump 3 via check valves 306 and 308, respectively. It communicates with the suction side of 12. The discharge side of the front pump 310 and the discharge side of the rear pump 31 are in communication with dampers 31 and 316 for absorbing the pulsation of the discharge pressure. The dambar 3 14 is in communication with a right front pump passage 3 18 provided corresponding to the right front wheel FR and a left front pump passage 3 20 provided corresponding to the left front wheel FL. On the other hand, the dambar 316 communicates with the hydraulic passage 252.

The right front pump passage 318 communicates with the hydraulic passage 248 via a right front pump solenoid 322 (hereinafter referred to as SPFL 322). Further, the left front pump passage 320 communicates with the hydraulic passage 250 through a left front pump solenoid 324 (hereinafter, referred to as SPFR 324). The SPFL 322 is in a position where the right front pump passage 318 and the hydraulic pressure passage 248 are brought into conduction when turned off, and shut off when turned on. Solenoid valve. Similarly, when the SPFR 324 is turned off, the left front pump passage 320 and the hydraulic passage 250 are brought into conduction, and when turned on, the SPFR 324 turns them off. A 2-position solenoid valve. Between the hydraulic passage 248 and the right front pump passage 318, a constant pressure release valve 326 that allows only the flow of fluid from the hydraulic passage 248 to the right front pump passage 318 is provided. It is arranged. Similarly, hydraulic passage 2 50 A constant pressure release valve 328 that allows only the flow of the fluid from the hydraulic pressure passage 250 to the left front pump passage 320 is provided between the hydraulic pump 250 and the left front pump passage 320. .

Wheel speed sensors 330, 332, 334, 336 are arranged near each wheel. ECU 2 1 0 detects the rotational speed V _W of each wheel based on the output signal of the wheel speed sensor 3 3 0-3 3 6. Further, a hydraulic sensor 338 is provided in the second hydraulic passage 240 communicating with the master cylinder 2 18. The ECU 210 detects the mass cylinder pressure PM / C based on the output signal of the fluid pressure sensor 338.

Next, the operation of the braking force control device according to the present embodiment will be described. The braking force control device of this embodiment realizes (1) the normal braking function, (2) the ABS function, and (3) the BA function by switching the state of various solenoid valves disposed in the hydraulic circuit.

(1) The normal braking function is realized by turning off all the solenoid valves provided in the braking force control device as shown in Fig. 12. Hereinafter, the state shown in FIG. 12 is referred to as a normal brake state. The control for realizing the normal brake function in the braking force control device is called normal brake control.

In the normal braking state shown in FIG. 12, the wheel cylinders 282 and 284 of the left and right front wheels FL and FR are both connected to the first hydraulic pressure of the mass cylinder 218 via the first hydraulic pressure passage 238. It communicates with room 220. The wheel cylinders 286 and 288 of the left and right rear wheels RL and RR communicate with the second hydraulic chamber 222 of the mass cylinder 218 via the second hydraulic pressure passage 240. . In this case, the foil cylinder pressure P _{W / C} of the foil cylinders 282 to 288 is always controlled to be equal to the master cylinder pressure PM _{/ C.} Therefore, according to the state shown in FIG. 12, the normal braking function is realized.

2) In the state shown in Fig. 12, the ABS function turns on the front pump 310 and the rear pump 312, and turns on the holding solenoid. This is realized by appropriately driving the depressurizing solenoid S ** H and the depressurizing solenoid S ** R according to the requirements of the ABS. Hereinafter, the control for realizing the ABS function in the braking force control device is referred to as ABS control.

The ECU 210 starts ABS control when the vehicle is in a braking state and an excessive slip rate is detected for any of the wheels.

The ABS control is started under the condition that the brake pedal 211 is depressed, that is, under the condition that the mass cylinder 218 generates the high mass cylinder pressure PM / C.

During the execution of the ABS control, the master cylinder pressure P _{M / C} is supplied via the first hydraulic passage 238 and the second hydraulic passage 240 to the hydraulic pressures respectively provided for the left and right front wheels. It is guided to passages 248 and 250 and to hydraulic passages 252 provided corresponding to the left and right rear wheels. Accordingly, when the holding solenoid S ** H is opened and the pressure reducing solenoid S ** R is closed under such a condition, the wheel cylinder pressure P _{w /} _c of each wheel is increased. be able to. Hereinafter, this state is referred to as (i) pressure increase mode.

If both the holding solenoid S ** H and the depressurizing solenoid S ** R are closed during the execution of the ABS control, the wheel cylinder pressure Pw / c of each wheel must be maintained. Can be. Hereinafter, this state is referred to as (ii) holding mode. Further, if the holding solenoid S ** H is closed and the pressure reducing solenoid S ** R is opened during the execution of the ABS control, the wheel cylinder pressure Pw / c of each wheel is set. Can be reduced in pressure. Hereinafter, this state is referred to as (iii) decompression mode.

The ECU 210 controls each wheel during the ABS control so that the above-described (i) boosting mode, (ii) holding mode, and (iii) depressurizing mode are appropriately realized for each wheel. The holding solenoid S ** H and the pressure reducing solenoid S ** R are controlled according to the slip state. When the holding solenoid S ** H and the depressurizing solenoid S ** R are controlled as described above, the wheel cylinder pressure P _{w / C of} all wheels is excessively large for the corresponding wheels. It is controlled to an appropriate pressure without generating a rate. As described above, according to the above control, the braking force control device can realize the ABS function.

When the decompression mode is performed on each wheel during the execution of ABS control, the brake fluid in the wheel cylinders 28 2 to 28 88, the front decompression passage 298 and the rear decompression passage 300 Through the front reservoir 302 and the rear reservoir 304. The brake fluid flowing into the front reservoirs 302 and the rear reservoirs 30 is pumped by the front pumps 310 and the rear pumps 310 and supplied to the hydraulic passages 248, 250, 252. You.

A part of the brake fluid supplied to the hydraulic passages 248, 250, and 252 flows into the wheel cylinders 282 to 288 when the pressure increasing mode is performed in each wheel. The remainder of the brake fluid flows into the mass cylinder 218 to compensate for the outflow of the brake fluid. Therefore, according to the present embodiment, an excessive stroke does not occur on the brake pedal 2 12 during execution of the ABS control.

FIGS. 13 to 15 show the state of the braking force control device for realizing the ③BA function. The ECU 210 implements the BA function by appropriately realizing the states shown in FIGS. 13 to 15 after the driver performs a braking operation that requests a quick rise of the braking force, that is, an emergency braking operation. To achieve. Hereinafter, the control for realizing the BA function in the braking force control device is referred to as BA control.

FIG. 13 shows an assist pressure increasing state realized during the execution of the BA control. The assist pressure increasing state is realized when it is necessary to increase the wheel cylinder pressure P _{w / C} of each wheel during execution of the BA control. In the system of the present embodiment, as shown in FIG. 13, the assist pressure increasing state during the BA control includes the reservoir cut solenoids SRCF 230, SR CR 232, and the mass cut solenoid SMF R 2. 4 2, SMF L 2 4 4, S MR 2 4 6 are turned on, and the front This is realized by turning on the pump 310 and the rear pump 312.

When the assist pressure increase state shown in Fig. 13 is realized, the brake fluid stored in the reservoir 224 is pumped up by the front pump 310 and the rear pump 312, and the hydraulic pressure is increased. It is supplied to passages 248, 250, 252. In the assist pressure increasing state, the internal pressure of the hydraulic pressure passages 248, 250, and 252 exceeds the valve opening pressure of the constant pressure release valves 254, 255, and 258, and the master cylinder pressure increases.ブレーキ Until the pressure becomes higher than Μ / C, the flow of the brake fluid from the hydraulic passages 248, 250, 252 to the mass cylinder 218 will be SMF R 242, Blocked by SMF L 2 4 4 and SMR 2 4 6.

For this reason, when the assist pressure increasing state shown in FIG. 13 is realized, thereafter, the hydraulic pressure passages 2488, 250, and 252 are connected to the mass cylinder pressure P

Higher hydraulic pressure is generated compared to M / C. In the assist pressure increasing state, the wheel cylinders 282 to 288 and the corresponding hydraulic passages 248, 250, and 252 are maintained in a conductive state. Therefore, when the assist pressure increase state is realized, thereafter, the wheel cylinder pressure Pw / c of all the wheels is quickly increased using the front pump 310 or the rear pump 312 as a hydraulic pressure source. The pressure is raised to a pressure exceeding PM / C.

By the way, in the assist pressure increasing state shown in FIG. 13, the hydraulic pressure passages 248, 250, and 252 are respectively connected to the mass through check valves 260, 262, 264. It communicates with evening cylinder 218. Therefore, when the master cylinder pressure P _{M / C} is larger than the wheel cylinder pressure P _{w / C} of each wheel, the master cylinder 218 is connected to the hydraulic pressure source even in the assist pressure increasing state. As a result, the wheel cylinder pressure P _{w / C} can be increased. FIG. 14 shows the assist pressure holding state realized during the execution of the BA control. The assist pressure holding state is realized when the wheel cylinder pressure Pw / c of each wheel needs to be held during the execution of the BA control. Assis As shown in Figure 14, the SRCF 230 and SRCR 232 are turned off, and the master cut solenoids SMF R2 42, SMF L 2 4 4 and SMR 2 4 6 are turned on as shown in Fig. 14. This can be realized by setting the front pump 310 and the rear pump 312 to the ON state.

In the assist pressure holding state shown in Fig. 14, the front pump 3 10 and the reservoir tank ₂ 24 and the rear pump 3 12 and the reservoir tank 2 24 4 power are applied to the SRCF 230 and SRCR 232, respectively. Therefore, it is shut off. Therefore, in the assist pressure holding state, no fluid is discharged from the front pump 310 and the rear pump 312 to the hydraulic passages 2488, 250, and 252. In addition, in the assist pressure holding state shown in FIG. 14, the hydraulic pressure passages 248, 250, 250 force, SMF R 242, SMF L 244, and SMR 246 cause mass flow. Substantially decoupled from cylinder 218. For this reason, according to the assist pressure holding state shown in FIG. 14, the wheel cylinder pressures Pw / c of all the wheels can be held at a constant value.

FIG. 15 shows a reduced assist pressure state realized during the execution of the BA control. The assist pressure reduction state is realized when it is necessary to reduce the wheel cylinder pressure Pw / c of each wheel during the execution of the BA control. The assist pressure reduction state is realized by turning on the front pump 3 10 and the rear pump 3 2 as shown in FIG.

In the reduced state of the assist pressure shown in FIG. 15, the front pump 310 and the rear pump 312 are separated from the reservoir tank 224. Therefore, no fluid is discharged from the front pump 310 and the rear pump 312 into the hydraulic passages 2488, 250, and 252. Further, in the assist pressure reduced state, the wheel cylinders 282-288 of each wheel and the master cylinder 2188 are in a conductive state. For this reason, if the axle pressure reduction state is realized, the wheel cylinder pressure P w / c of all wheels can be reduced using the master cylinder pressure PM as the lower limit. I

In the braking force control device of the present embodiment, when the BA control is started, first, (I) a start pressure increasing mode is executed. (I) The start pressure increase mode is realized by maintaining the assist pressure increase state shown in FIG. 13 during the predetermined pressure increase time T _STA . As described above, when the assist pressure increasing state is realized, the wheel cylinder pressure P _{w / C} of each wheel is set to the master cylinder pressure P _{M using the} front pump 310 or the rear pump 312 as a hydraulic pressure source. _The pressure is increased to a pressure exceeding _{/ C.} Therefore, the wheel cylinder pressure Pw / c of each wheel is immediately increased to a pressure exceeding the mass cylinder pressure PM _{/ C} after the execution of the BA control.

After the above-mentioned (I) start pressure increase mode ends, in response to the driver's brake operation, (II) assist pressure increase mode, (ΠΙ) assist pressure decrease mode, (IV) Any of the assist pressure holding mode, (V) assist pressure gradual increase mode, and (VI) assist pressure gradual decrease mode is executed. C During the BA control, the master cylinder pressure P _M / c If the pressure is rapidly increased, it can be determined that the driver is requesting a larger braking force. In this case, in the braking force control device of the present embodiment, (Π) the assist pressure increasing mode is executed. The (II) assist pressure increasing mode is realized by maintaining the assist pressure increasing state shown in FIG. 13 as in the above (I) starting pressure increasing mode. According to the assist pressure increasing state, the wheel cylinder pressure P _{w / c} of each wheel can be quickly increased using the front pump 310 and the rear pump 312 as a hydraulic pressure source. Therefore, according to the above processing, the intention of the driver can be accurately reflected on the wheel cylinder pressure Pw / c.

If the master cylinder pressure PM _{/ C} is rapidly reduced during the execution of the BA control, it can be determined that the driver intends to reduce the braking force quickly. In this embodiment, in this case, (III) the assist pressure reduction mode is executed. The UU) assist pressure reduction mode is realized by maintaining the assist pressure reduction state shown in FIG. 15 described above. According to Assist pressure decreasing state, as described above, it is possible to quickly reduced pressure towards the Hoirushiri emissions Da pressure P _{w / C} of each wheel to the mass evening Siri Nda圧P _M / _C. Therefore, according to the above processing, the driver's intention can be accurately reflected on the wheel cylinder pressure P _{w / C.}

If the master cylinder pressure P _M / c is maintained at a substantially constant value during the execution of the BA control, it can be determined that the driver intends to maintain the braking force. In this embodiment, in this case, (IV) the assist pressure holding mode is executed. (IV) The assist pressure holding mode is realized by maintaining the assist pressure holding state shown in FIG. 14 described above. According to the assist pressure holding state, the wheel cylinder pressure Pw / c of each wheel can be maintained at a constant value as described above. Therefore, according to the above processing, the driver's intention can be accurately reflected on the wheel cylinder pressure Pw / c.

If the master cylinder pressure PM _{/ C} is gradually increased during execution of the BA control, it can be determined that the driver intends to gradually increase the braking force. In this embodiment, in this case, (V) the assist pressure reduction mode is executed. (V) The assist pressure gradual increase mode is realized by repeating the assist pressure increasing state shown in FIG. 13 and the assist pressure holding state shown in FIG. 14 above. (V) According to the assist pressure gradual increase mode, the wheel cylinder pressure P _{w / C} of each wheel can be increased stepwise using the front pump 310 and the rear pump 312 as a hydraulic pressure source. Therefore, according to the above processing, the driver's intention can be accurately reflected on the wheel cylinder pressure P _{w / C.}

If mass evening Siri Nda圧P _M / c during execution of the BA control is slowly reduced pressure, it can be determined that the driver is intended to reduce gradually the brake force. In this embodiment, in this case, the (VI) assist pressure gradual decrease mode is executed. (VI) The assist pressure moderation mode is realized by repeating the assist pressure reduction state shown in FIG. 15 and the assist pressure holding state shown in FIG. 14 described above. (VI) Assist pressure moderation mode Then, the wheel cylinder pressure P _{w / C} of each wheel can be reduced stepwise toward the master cylinder pressure PM _{/ C.} Therefore, according to the above processing, the driver's intention can be accurately reflected on the wheel cylinder pressure P _{w / C.}

According to the above-described processing, the wheel cylinder pressure Pw / c can be increased to a pressure higher than the mass cylinder EP _{M /} c immediately after the driver performs the emergency braking operation, and In addition, the boosted wheel cylinder pressure P _{w / C} can be increased according to the driver's brake operation.

In the braking force control device according to the present embodiment, when the above-described BA control is started, the wheel cylinder pressure P _{w / C of} each wheel is immediately increased, so that an excessive slip on any one of the wheels is achieved. In some cases, the rate may increase. In such a case, the ECU 210 starts control (BA + ABS control) for realizing both the BA function and the ABS function. Hereinafter, the operation of the braking force control device accompanying the execution of the BA + ABS control will be described with reference to FIGS. 16 to 21 together with FIGS. 13 to 15 described above.

In the braking force control device of the present embodiment, when the driver performs a braking operation intended to reduce the braking force during the execution of the BA + ABS control, the wheel cylinder pressure Pw / c of the ABS target wheel is increased by the ABS. It is necessary to reduce the wheel cylinder pressure P _{w / C} of the non-ABS wheels toward the master cylinder pressure P _{M / C} while controlling the pressure according to the control requirements. Hereinafter, this request is referred to as the assist pressure reduction ABS request.

The assist pressure decompression ABS request is executed for the ABS target wheel of the holding solenoid S ** H and the decompression solenoid S ** R while realizing the assist E decompression state shown in Fig. 15 above. This is realized by appropriately controlling the components corresponding to the requirements according to the ABS control requirements. Hereinafter, a state in which the above control is performed in the braking force control device is referred to as an assist pressure reduction ABS state. The ABS pressure request is generated when the driver intends to reduce the braking force, that is, when it is not necessary to increase the wheel cylinder pressure Pw / c of any of the wheels. Thus, in a situation where Assist pressure '减圧AB S request has occurred, while depressurizing the Hoirushiri emissions Da pressure Pw / c of the A BS asymmetrical wheel, the Hoirushiri Nda圧P _{w /} c of the ABS subject wheel It must be able to hold and depressurize.

In the above-described assist pressure reduction ABS state, all the holding solenoids S ** H are in communication with the master cylinder 218. Therefore, according to the assist pressure decreasing AB S state may Rukoto the male proper flashing towards the mass evening Siri Nda圧P _M / _C to Hoirushi Li Nda圧P _{w / C} of AB S non-target wheels. Further, in this situation, when the (ii) holding mode or the (iii) decompression mode is realized for the ABS target wheel, the wheel cylinder pressure P _{w / C} of the ABS target wheel can be held or reduced. As described above, according to the assist pressure decompression ABS described above, the function to be realized when the assist pressure decompression ABS request is generated can be appropriately realized.

In the braking force control device according to the present embodiment, when the driver performs a braking operation intended to increase the braking force during the execution of the BA + ABS control, the wheel cylinder pressure Pw / c of the ABS target wheel is increased by the ABS. It is necessary to increase the wheel cylinder pressure Pw / c of the non-ABS wheels in the region exceeding the master cylinder pressure P _{M / C} while controlling the pressure according to the control requirements. Hereinafter, this requirement is referred to as an assist pressure increase ABS requirement.

The APS request for the assist pressure increase ABS applies to the ABS target of the holding solenoid S ** H and the pressure reduction solenoid S ** R while realizing the assist pressure increase state shown in Fig. 13 above. It can also be realized by controlling the wheel corresponding to the ABS control request. That is, for example, when the left front wheel FL is an ABS target wheel, the SFLH 268 and SF LR 276 are controlled according to the ABS control request while achieving the assist pressure increasing state shown in FIG. If controlled, the left front wheel FL wheel While controlling the Rushiri Nda圧P _{w / C} pressure corresponding to the requirements of the ABS control, the other wheels FR, RL, the Hoirushiri Nda圧P _{w / C} of RR mass evening than in silicon Nda圧P _{M / C} Pressure can be increased in a high region.

However, when the ABS control is started for the left front wheel FL, the holding solenoid SFLH 268 corresponding to the left front wheel FL is thereafter operated for the left front wheel FL except for a short time when the pressure increase mode is executed. The valve is closed. For this reason, after the ABS control is started for the left front wheel FL, most of the brake fluid discharged from the front pump 310 flows into the wheel cylinder 282 of the right front wheel FR which is a non-ABS wheel.

The discharge capacity of the front pump 310 is set so that the wheel cylinder pressures Pw / c of the left and right front wheels FL and FR can be simultaneously increased with an appropriate pressure increasing gradient. For this reason, under the condition that most of the brake fluid discharged from the front pump 310 flows into the wheel cylinder 282 of the right front wheel FR, which is a wheel not subject to ABS, the wheel cylinder pressure Pw of the right front wheel FR An excessive pressure gradient occurs at / c.

Furthermore, as described above, in a situation where an excessive pressure increase gradient occurs in the wheel cylinder pressure P _{w / C} of the right front wheel FR, when the pressure increase mode is executed for the left front wheel FL, the left front wheel FL The wheel cylinder pressure P _{w / C of this case} may be excessively increased. If the wheel cylinder pressure Pw / c of the ABS target wheel is excessively increased due to (i) execution of the pressure increase mode, it is necessary to execute (ii) pressure reduction mode again for that wheel, and hunting for the ABS control is performed. Disadvantageously easily occurs.

In this regard, while realizing the assist pressure increasing state shown in Fig. 13 above, the holding solenoid S ** H and the depressurizing solenoid S ** R that correspond to the ABS target wheel are required for ABS control. The method that satisfies the assist pressure increase ABS requirement by performing control in accordance with the above is not necessarily the optimal method for realizing BA + ABS control in the braking force control device of the present embodiment. Fig. 16 shows the state realized by the braking force control device when the ABS request is made with the left front wheel FL as the ABS target wheel (hereinafter referred to as the assist pressure boost ABS state). One form is shown. The assist pressure increase ABS state in which the front left wheel FL is set as the ABS target wheel is realized by controlling the braking force control device so that the following conditions (a) to (d) are satisfied.

(a) The front reservoir cut solenoid SRCF 230 which is turned on in the assist pressure increasing state shown in FIG. 13 is turned off. Specifically, (a-1) the reservoir cut solenoid SRCR 232, and the mass cut solenoid SMFR 242, SMF L 244 and SMR 246 are turned on, and (A-2) Turn on the front pump 310 and the rear pump 312.

(b) The holding solenoid SF LH 268 and the pressure reducing solenoid SFLR 276 of the left front wheel FL, which is the ABS target wheel, are controlled as follows in accordance with the ABS control request. (B-1) When (ii) holding mode and (iii) decompression mode are required by ABS control, control is performed in the same manner as when ABS control is executed alone. (B-2) When the ABS control requires execution of (i) the pressure increase mode, the pressure increase mode is executed for a predetermined time shorter than when the ABS control is executed alone. I do.

(c) The holding solenoid SFRH266 of the right front wheel FR belonging to the same system as the ABS target wheel is repeatedly turned on / off at a predetermined duty ratio.

(d) The master cut solenoids SMFR 242 and SMFL 244 belonging to the system including the left front wheel FL, which is the A B S target wheel, are

FL (iii) Turn off (valve open) in synchronization with the execution of the pressure reduction mode.

According to the above condition (a), when the assist pressure increase ABS request is generated, the front pump 310 that belongs to the system including the ABS target wheel is simultaneously operated. The reservoir tank 222 can be shut off. In this case, since the brake fluid sucked into the front pump 310 is limited to only the fluid flowing out of the foil cylinder 284, the hydraulic pressure generated on the discharge side of the front pump 310 is compared. It is suppressed to extremely low pressure. As a result, a state is formed which is advantageous in preventing hunting of the ABS control and in suppressing the pressure gradient of the wheel cylinder pressure P _{w / C} of the right front wheel FR which is a non-ABS target wheel.

According to the condition (b) above, the time during which (i) the pressure increase mode is executed with the left front wheel F, which is the ABS target wheel, is reduced as compared with the case where the ABS control is executed alone. You. When the execution time of (i) the pressure increase mode is shortened, (i) the pressure increase amount generated in the wheel cylinder pressure P _{w / C} of the left front wheel FL due to the execution of the pressure increase mode is suppressed. In such a situation, even if a higher hydraulic pressure is generated upstream of the SFLH 268 than usual, hunting hardly occurs in the ABS control.

According to the condition (c) above, for the right front wheel FR belonging to the same system as the ABS target wheel, the state in which the brake fluid flows into the wheel cylinder 282 and the state in which the brake fluid is blocked are determined to be a predetermined value. Repeated at duty ratio. In this case, the wheel cylinder pressure P _{w / C} of the right front wheel FR increases with an appropriate pressure increasing gradient even if a higher hydraulic pressure is generated upstream than the SF RH 266 as compared with normal times.

According to the above condition (d), the discharge side of the front pump 310 and the master cylinder 211 are synchronized with the time when the brake fluid flowing out of the wheel cylinder 284 is pumped by the front pump 310. 8 is made conductive. In this case, since the brake fluid can flow into the master cylinder 2 18, the hydraulic pressure generated on the discharge side of the front pump 310 is suppressed to a relatively low pressure. As a result, a state is formed which is advantageous in preventing hunting of the ABS control and in suppressing the pressure increase gradient of the wheel cylinder pressure Pw / c of the right front wheel FR which is a non-ABS target wheel. For this reason, according to the above-described assist pressure increase ABS state, the wheel cylinder pressure P _W / _C of the ABS target wheel can be controlled in the same manner as when the ABS control is executed alone, The wheel cylinder pressure Pw / c of the wheel not subject to ABS is increased with the same pressure gradient as when the wheel cylinder pressure P * / _C is required to be increased under the condition that BA control is executed alone. be able to. As described above, according to the above-described astride pressure increase ABS state, the function to be realized when the assist pressure increase ABS request occurs can be appropriately realized.

In the braking force control device of the present embodiment, if the driver performs a braking operation intended to maintain the braking force during the execution of the BA + ABS control, the wheel cylinder pressure P _{w / C} of the ABS target wheel is increased. There is a need to maintain the wheel cylinder pressure P _{w / C} of the ABS non-target wheels while controlling the pressure to meet the ABS control requirements. Hereinafter, this request is referred to as an assist pressure holding ABS request.

Assist pressure holding When an ABS request occurs, the holding pressure S S * * H and the pressure reduction solenoid S * * R are realized while maintaining the assist pressure holding state shown in Fig. 14 above. By controlling the wheel corresponding to the target wheel in accordance with the request of the ABS control, the wheel cylinder pressure P _{w / C} of the ABS target wheel is controlled to a pressure corresponding to the request of the ABS control, and It is possible to maintain the wheel cylinder pressure Pw / c of the ABS non-target wheels belonging to the system that does not include the ABS target wheels in the same system.

That is, for example, when an assist pressure holding ABS request is made with the left front wheel FL as an ABS target wheel, S FLH 268 and S FLR 276 while realizing the assist pressure holding state shown in FIG. If the front left wheel FL is controlled according to the ABS control request, the (ii) holding mode and (iii) the pressure reduction mode and the front pump 310 are used as the hydraulic pressure source for the left front wheel FL. Pressure mode can be realized. Therefore, the wheel cylinder pressure Pw / c of the left front wheel FL is increased according to the ABS control requirements. Can be controlled. In the above situation, the rear wheel system that does not include the ABS target wheel is maintained in the same manner as the state shown in FIG. Therefore, for the left and right rear wheels RL and RR, their wheel cylinder pressures Pw / c can be maintained as in the case where the BA control is executed alone.

However, according to the above-described method, (iii) after the decompression mode is executed for the left front wheel FL, the brake fluid flowing out of the wheel cylinder 284 is pumped by the front pump 310, and the wheel cylinder of the right front wheel FR is driven. It flows into 2 82. For this reason, the right front wheel FR belonging to the front wheel system having the ABS target wheel in the same system cannot meet the requirement of the BA control, that is, cannot maintain the wheel cylinder pressure P _{w / C.}

Fig. 17 shows an example of the state realized by the braking force control system when the request for maintaining the assist pressure ABS with the left front wheel FL as the ABS target wheel (hereinafter referred to as the assist pressure holding ABS state). Show. The assist pressure holding ABS state in which the front left wheel FL is the ABS target wheel is realized by controlling the braking force control device so that the following conditions (e) to (g) are satisfied.

(e) Among the holding solenoids S ** H that are turned off in the assist pressure holding state shown in Fig. 14 above, the right front wheel FR that is an ABS non-target wheel that has an ABS target wheel in the same system Turn the holding solenoid SFRH266 of the ON state (closed state). Specifically, (e-1) the mass cut solenoid SMFR 242, SMF L 244, and SMR 246 are turned on, and (e-2) the front pump 310 and the rear pump 3 1 2 is turned on, and (e-3) SFRH 266 is turned on.

(f) The holding solenoid S FLH 268 and the depressurizing solenoid S FLR 276 of the left front wheel FL, which is the target wheel for ABS, are responded to the ABS control request by the same method as the condition (b) above. That is, (0 The control time is controlled by a pattern in which the maintenance time of 95 is shorter than usual.

(g) The SMF R 242 and SMF L 244 belonging to the system including the left front wheel FL, which is the ABS target wheel, are subjected to the same method as the condition (c) above, that is, the left front wheel FL (iii) Control so as to be in the OFF state (valve open state) in synchronization with the time when the pressure reduction mode is executed.

According to the above condition (e), when the assist pressure increasing ABS request is generated, the wheel cylinder 282 of the right front wheel FR, which is a non-ABS target wheel belonging to the system including the ABS target wheel, is connected to the front pump. It can be separated from 310. In this case, since the brake fluid discharged from the front pump 310 does not flow into the wheel cylinder 282, the wheel cylinder pressure Pw / c of the right front wheel FR is appropriately maintained according to the request of the BA control.

According to the condition (f), as in the case where the condition (b) is realized, (i) when the pressure increase mode is executed on the left front wheel FL, which is the ABS target wheel, The amount of pressure increase generated in the wheel cylinder pressure Pw / c can be suppressed.

Further, according to the condition (g), similarly to the case where the condition (d) is realized, the time when the brake fluid flowing out of the wheel cylinder 284 is pumped by the front pump 310 is determined. Synchronously, the discharge side of the front pump 310 and the master cylinder 218 can be brought into conduction.

Therefore, according to the assist pressure holding ABS state described above, the wheel cylinder pressure P _{w / C} of the ABS target wheel can be controlled in the same manner as in the case where the ABS control is executed alone, and all ABS S The wheel cylinder pressure P _{w / C} of the target wheel can be appropriately maintained as in the case where the BA control is executed alone. As described above, according to the above-described assist system pressure holding ABS state, the function to be realized when the assist pressure holding ABS request is generated can be appropriately realized. After the BA control is started, the braking force control device according to the present embodiment appropriately controls the above-described assist pressure increase ABS state and assist pressure when any of the wheels has an excessive slip rate. By realizing the holding ABS state and the assist pressure reduction ABS state, ① While suppressing the wheel cylinder pressure P _W / c of the ABS target wheel to the pressure required by the ABS control, ② The wheel cylinder pressure P _{w / C} is controlled to the pressure required by BA control.

FIG. 18 shows a flow chart of an example of a reservoir cut-off noise control routine executed by the ECU 210 to realize both the BA control and the BA + ABS control described above. The ECU 210 executes the routine shown in FIG. 18 for each of the front wheel system to which the left and right front wheels FL, FR belong, and the rear wheel system to which the left and right rear wheels RL, RR belong. The ECU 210 executes the routine shown in FIG. 18 to generate the reservoir cut solenoid SRCF 230 and SRCR 232 (hereinafter collectively referred to as the reservoir cut solenoid SRC *). ) Control the state of. The routine shown in FIG. 18 is a periodic interrupt routine that is started every predetermined time. When the routine shown in FIG. 18 is started, first, the processing of step 400 is executed.

In step 400, it is determined whether or not BA control is being performed in the braking force control device. As a result, if it is determined that the BA control is not being executed, the current routine is terminated without any further processing. On the other hand, when it is determined that the BA control is being executed, the process of step 402 is next executed.

In step 402, it is determined whether or not one or more ABS target wheels exist in the system to be controlled by this routine. As a result, if it is determined that one or more ABS target wheels exist, the process of step 404 is executed next. On the other hand, if it is determined that the ABS target wheel does not exist in the system to be controlled, the process of step 406 is executed next. In step 404, the reservoir SRC * belonging to the system to be controlled is set to the off state (valve closed state). When the process of step 404 is completed, the current routine is completed.

In step 406, the reservoir cut solenoid SRC * belonging to the system to be controlled is controlled as usual in response to the BA control request. When the processing of step 406 ends, the current routine ends.

As shown in FIGS. 13 to 15 above, during execution of the BA control, the reservoir cut solenoid SRC * is turned on when the assist pressure increasing state shown in FIG. 13 is required (valve open state). Is required. On the other hand, as shown in Fig. 15 to Fig. 17 above, while BA + ABS control is being executed, of the reservoir cut solenoid SRC *, those belonging to the system in which no ABS target wheels exist are under BA control. It is necessary to control in the same way as described above, and to always keep at least one wheel belonging to the system including the ABS target wheel in the off state (valve closed state). According to the control routine shown in FIG. 18 described above, such a request can be appropriately satisfied.

Further, according to the control routine shown in FIG. 18 described above, the amount of brake fluid flowing out of the reservoir tank 224 during execution of the BA control can be suppressed. If a large amount of brake fluid flows out of the reservoir tank 224 during BA control, the amount of brake fluid that flows back to the cylinder 218 will increase, causing damage to the cup that constitutes the check valve Occurs, and the brake pedal 2 1 2 is incorrectly returned toward the home position. On the other hand, according to the control routine shown in FIG. 18 described above, it is possible to prevent such a problem from occurring.

FIG. 19 shows a flowchart of an example of a control method selection routine executed by the ECU 210 to implement both the above-described BA control and BA-10 ABS control. The ECU 210 is equipped with a routine shown in Fig. 19 for each wheel. Run. By executing the routine shown in FIG. 19, the ECU 210 selects the control method of the holding solenoid S * H and the pressure reducing solenoid S * R for each wheel. The routine shown in FIG. 19 is a periodic interrupt routine started at a predetermined time interval. When the routine shown in FIG. 19 is started, first, the processing of step 410 is executed. In step 410, it is determined whether or not BA control is being performed in the braking force control device. As a result, if it is determined that the BA control is not being executed, the current routine is terminated without any further processing. On the other hand, if it is determined that the BA control is being executed, the process of step 412 is performed next.

In step 412, it is determined whether or not a wheel to be controlled by this routine (hereinafter, this wheel is denoted by a reference numeral) is an ABS target wheel. As a result, if it is determined that the control target wheel ** is the ABS target wheel, then the processing of steps 414 is executed. On the other hand, if it is determined that the control target wheel ** is not the ABS target wheel, then the process of step 416 is executed.

In step 414, the control method of the holding solenoid S ** H and the pressure reducing solenoid S ** R provided corresponding to the control target wheel ** is determined to be ABS control. After that, S ** H * S ** R, whose control method is ABS control, will be appropriately changed according to the slip state of the wheel to be controlled (i) the pressure increase mode, (ii) the hold mode and (Iii) Control is performed so that the decompression mode is realized. When the processing of this step 4 14 is completed, the current routine is completed.

In step 416, it is determined whether or not another wheel belonging to the same system as the control target wheel is an ABS target wheel. As a result, when it is determined that the other wheel is not the ABS target wheel, the process of step 18 is executed next. On the other hand, if it is determined that the other wheel is the ABS target wheel, the process of step 420 is executed next. In Steps 4 and 8, the control wheels ** The control method of the holding solenoid S ** H and the pressure reducing solenoid S ** R is determined by BA control. S * H and S ** R for which the control method is BA control in this step 418 will be described later in detail as shown in FIGS. 13 to 15 according to the BA control request. Is always turned off. When the processing of this step 418 is completed, this routine is completed.

In step 420, the control method of the holding solenoid S ** H and the pressure reducing solenoid S ** R provided corresponding to the control target wheel ** is determined as the BA pressure increase gradient suppression control. S ** H and S ** R for which the control method is set to BA control in step 420 are thereafter appropriately controlled according to the requirement of BA + ABS control.

Specifically, when the assist pressure increase ABS request is generated by BA + ABS control, the holding solenoid S ** H is maintained while the pressure reducing solenoid S ** R is maintained in the off state. Is turned on / off at a predetermined duty ratio. When the assist pressure holding ABS request is generated by the BA + ABS control, the holding solenoid S ** H is kept on and the pressure reducing solenoid S ** R is kept off. Further, when the assist pressure reduction request is generated by the BA + ABS control, both the holding solenoid S ** H and the pressure reduction solenoid S ** R are maintained in the off state. When the process of step 420 ends, the current routine ends.

As shown in FIGS. 13 to 15 above, when the BA control is executed independently, that is, when there is no ABS target wheel in any of the front and rear systems, all the holding solenoids S ** are held. H and the decompression solenoid S ** R must be kept off at all times. Also, as shown in Fig. 15 to Fig. 17, during BA + ABS control, the holding solenoid S ** H and the depressurizing solenoid S ** R correspond to the ABS target wheels. Are controlled according to the ABS requirements, and are compatible with ABS non-target wheels belonging to a system where there is no ABS target wheel When the ABS pressure request is raised, the one provided for the ABS non-target wheels belonging to the same system as the ABS target wheels is turned off. It is turned off when the assist pressure depressing ABS request is made so that the condition (e) is satisfied so that the condition (c) is satisfied when the assist pressure holding ABS request is made Need to be controlled. According to the control routine shown in FIG. 19 above, such a demand can be satisfied appropriately.

Fig. 20 shows the (a) pressure increase generated in the wheel cylinder pressure Pw / c of the ABS target wheel when the pressure increase mode is executed during BA + ABS control, and the ABS control is executed independently. (I) When the pressure increase mode is executed, the ECU 210 is executed to make the pressure increase amount generated in the wheel cylinder pressure _PW / _C of the ABS target wheel substantially equal to the pressure increase amount. 5 shows a flowchart of an example of an ABS control method selection routine.

The ECU 210 executes the routine shown in FIG. 20 for each wheel. The ECU 210 drives the holding solenoid S ** H and the pressure reducing solenoid S ** R provided corresponding to the ABS target wheel by executing the routine shown in FIG. The routine shown in FIG. 20 is a periodic interrupt routine that is started every predetermined time. When the routine shown in FIG. 2 0 is started, first, in Step 4 3 _c Step 4 3 0 processing is executed zero, flag XABS * * is "1" is determined whether or not being Bok set . The flag XABS ** is a flag that is set to "1" when the wheel to be controlled in this routine is an ABS target wheel. Therefore, if the control target wheel ** is not the ABS target wheel, it is determined in this step 430 that XAB S * = 1 is not established. In this case, the process of step 432 is executed next.

In step 43, it is determined whether or not the execution condition of the ABS control has been satisfied for the control target wheel **. As a result, if it is determined that the execution condition of the ABS control is not satisfied, the current routine is terminated without any further processing. Meanwhile, ABS control If it is determined that the execution condition is satisfied, then the process of step 434 is performed.

In step 4 3 4, the flag XABS ** is set to "1" to indicate that the control target wheel ** has become the ABS target wheel. Upon completion of the process of step 434, the process of step 436 is executed.

In step 436, it is determined whether or not the BA control is being executed. As a result, when the BA control is not being executed, it can be determined that the ABS control is executed independently after the execution condition of the ABS control is satisfied for the wheel to be controlled. In this case, the process of step 438 is performed next. On the other hand, if it is determined in step 436 that BA control is being executed, it is determined that BA + ABS control is executed after the ABS control execution condition is satisfied for the control target wheel **. be able to. In this case, the process of step 450 is performed next.

In step 438, processing for setting a normal map to the ABS map is executed. The ABS map is a map that is referred to when the holding solenoid S ** H and the pressure reducing solenoid S ** R are driven according to the ABS control request. In the normal map, which is set as the ABS map in step 438, an appropriate pressure increasing gradient is generated in the wheel cylinder pressure P _{w / C} of the ABS target wheel when the ABS control is executed alone. The drive pattern has been set. When the process of step 438 is completed, the process of step 4422 is next performed.

In step 440, processing for setting the pressure increase suppression map in the ABS map is executed. The boost pressure suppression map is a drive pattern that generates an appropriate pressure gradient in the wheel cylinder pressure P _W / _C of the ABS target wheel during the execution of the BA + ABS control. ϋ) A drive pattern has been set in which the maintenance time of the pressure increase mode is shortened. When the processing of this step 44 is completed, the processing of step 44 Is executed.

In step 4442, the holding solenoid S ** H and the decompression solenoid S * are determined based on the ABS map selected in the above step 438 or 4400 and the slip state of the controlled wheel **. * R is controlled. By executing the processing of this step 442, (i) the low pressure mode, (ii) the holding mode, and (iii) the decompression mode are realized as appropriate for the ABS target wheel. When the processing of this step 4 42 is completed, the current routine ends.

If it is determined in step 430 that XSBS ** = 1 is satisfied, then the process of step 444 is executed.

In step 44, it is determined whether the condition for terminating the ABS control is satisfied. As a result, if it is determined that the condition for terminating the ABS control is not satisfied, then the above-described processing of step 442 is executed. In step 44, the holding solenoid S ** H and the decompression solenoid S ** R are driven according to the ABS map set before the previous processing cycle. On the other hand, if it is determined in step 444 that the condition for terminating the ABS control is satisfied, then the process of step 446 is executed.

In step 446, a process of setting the flag XABS ** to "0" is executed. After the process of this step 446 is executed, the ABS control is not executed for the wheel ** until the execution condition of the ABS control is satisfied again for the controlled wheel **. When the processing of this step 446 ends, the current routine ends.

According to the above processing, when the ABS control is executed independently, the ABS control can be executed for each wheel in the drive pattern according to the normal map. When the BA + ABS control is executed, the ABS control can be executed for each wheel in a drive pattern according to the pressure increase suppression map. Therefore, according to the braking force control device of the present embodiment, when the ABS control is executed independently, and when BA + A In both cases where the BS control is executed, the wheel cylinder pressure P _{w / C} of the ABS target wheel can be appropriately controlled without hunting in control.

Fig. 21 shows that the ECU 210 executes the 88 + 88 control to prevent an unreasonably high hydraulic pressure from being generated on the discharge side of the pump belonging to the system including the target wheel. 5 is a flowchart showing an example of a master power solenoid control routine to be performed. The ECU 210 executes the routine shown in FIG. 21 for each system of the front and rear wheels. The ECU 210 executes the routine shown in FIG. 21 so that the mass cut solenoids SMF R242, SMF L244 and SMR246 belonging to the system having the wheels to be subjected to the ABS are provided. (Hereinafter, these are collectively referred to as mass cut solenoid SM **). The routine shown in FIG. 21 is a periodic interrupt routine that is started every predetermined time. When the routine shown in FIG. 21 is started, first, the processing of step 450 is executed.

In step 450, it is determined whether or not the BA control is being executed. As a result, if it is determined that the BA control is being executed, the process of step 452 is next performed. On the other hand, if it is determined that the BA control is not being executed, the process of step 454 is next performed. In step 452, processing is performed to turn off the mass cut solenoid SM ** belonging to the system to be controlled by this routine, in the off state (valve open state). When the processing of step 452 is completed, the current routine is completed.

In step 454, it is determined whether or not there is a wheel in which (iii) the decompression mode is realized in the system to be controlled by the routine according to the ABS control request. As a result, (iii) when it is determined that there is no wheel in which the decompression mode is realized, the process of step 456 is next performed.

In step 4 56, the system that is controlled by this routine The mass cut solenoid SM ** to which it belongs is controlled in the same way as during BA control. Specifically, when the boosting or holding of the wheel cylinder pressure Pw / c is requested by the BA control, the wheel cylinder pressure is turned on (valve closed state), and the reduction of the wheel cylinder pressure Pw / c is requested by the BA control. If it is set, it is controlled to the off state (valve open state) (see SM ** in FIGS. 13 to 15 above and SMR 246 in FIGS. 16 and 17 above). When the processing of this step 456 is completed, the current routine ends.

On the other hand, if it is determined in step 454 that there is (ii i) a wheel in decompression mode in the system to be controlled, then the process in step 452, that is, The process of turning off the master cut SM ** belonging to the system is executed. According to the above processing, when the (iii) decompression mode is executed on the ABS target wheel during the execution of the BA + ABS control, the pump belonging to the same system as the ABS target wheel is activated. When pumping the brake fluid, the discharge side of the pump and the mass cylinder 218 are always in a conductive state. In this case, since the brake fluid discharged from the pump can flow into the master cylinder 218, the brake fluid discharged from the pump cannot flow into the wheel cylinder of the ABS target wheel. There is no unreasonably high hydraulic pressure on the discharge side of the pump. For this reason, according to the braking force control device of the present embodiment, hunting does not occur in the ABS target wheel during the BA + ABS control, and the same control as the ABS target wheel is performed. It is possible to reliably prevent the wheel cylinder pressure Pw / c of the ABS non-target wheels belonging to the system from being increased by an excessive pressure increase gradient.

By the way, in the above-mentioned embodiment, only when the (iii) decompression mode is executed on the ABS target wheel during the execution of the BA + ABS control, the master power solenoid belonging to the same system as the wheel is operated. SM ** is to be opened, but the present invention is not limited to this. Instead, the master cutter SM ** may be kept open during the execution of the BA + ABS control.

In the above embodiment, the master cylinder 218 is used as the “operating hydraulic pressure generating means”, the front pump 310 and the rear pump 318 are used as the “assist pressure generating means”, and the hydraulic pressure passages 248 are used. , 250, 252 force (high pressure passage), master cut solenoid SM * * force "^" operating fluid pressure cut-off mechanism ", front pressure reduction passage 298 and rear pressure reduction passage 300 force In the "low pressure passage", the holding solenoid S ** H and the pressure reducing solenoid S ** R force In the "conduction state control mechanism", the front reservoir 302 and the rear reservoir 304 are connected to the "low pressure source" and The “second low pressure source” corresponds to the “second low pressure source”, and the reservoir tank 224 corresponds to the “first low pressure source”.

Further, in the above embodiment, the ECU 210 executes the routine shown in FIG. 20 so that the “ABS control means” and the “ABS pattern selecting means” can be used. By executing the routine shown in FIG. 19, the “BA pressure increase gradient suppression means” is realized, and by the ECU 210 executing the routine shown in FIG. 18 above, “the low pressure source cutting means” is realized. ing.

Further, in the above embodiment, the ECU 210 always sets the master cut solenoid SM ** to the OFF state (valve open state) during the execution of the BA + ABS control, so that the "high-pressure passage opening means" is provided. Is achieved. Next, a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 22 shows a system configuration diagram of a pump-up type braking force control device (hereinafter, simply referred to as a braking force control device) corresponding to the fifth embodiment of the present invention. In FIG. 22, the same components as those shown in FIG. 12 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

The braking force control device of the present embodiment is a device suitable as a braking force control device for a front engine type front drive type vehicle (FF vehicle). You. The braking force control device of the present embodiment is controlled by the ECU 210. The ECU 210 uses the recover cut solenoids SRC and SRC- ₂ to be described later as the SRC * of the above steps 404 and 406, and the mass cut solenoids SMC- and 511 to be described later. and _SMC-2 5 1 4 a by executing the control routine shown in FIG. 1 8 to 2 1 with a SM * * in step 4 5 2 and 4 5 6, a fourth embodiment described above O Control the operation of the braking force control device in the same way as

The braking force control device includes a brake pedal 2 1 2. A brake switch 214 is provided in the vicinity of the brake pedal 211. The ECU 210 determines whether or not the brake pedal 2 12 is depressed based on the output signal of the brake switch 21. The brake pedal 2 12 is connected to the vacuum booster 2 16. The vacuum booster 216 is fixed to the mass cylinder 218. A first hydraulic chamber 220 and a second hydraulic chamber 222 are formed inside the master cylinder 218. Inside the first hydraulic chamber 222 and the second hydraulic chamber 222, the master cylinder pressure P corresponding to the resultant force of the brake depression force F and the assist force Fa generated by the back-up booth 2 16 _{M / C} occurs.

A reservoir tank 224 is provided above the master cylinder 218. A first reservoir passage 500 and a second reservoir passage 502 communicate with the reservoir tank 224. A first reservoir cut solenoid 504 (hereinafter referred to as SRC-, 504) communicates with the first reservoir passage 504. Similarly, the second reservoir passage 5 0 2, the second reservoir forces Tsu Tosorenoi de 5 0 6 (hereinafter, referred to as SRC one ₂ 5 0 6) is communicated.

A first pump passage 508 communicates with the SRC—, 504. Similarly, the SR _C-2 5 0 6, the second pump passage 5 1 0 are communicated. SR C-, 504 is turned off, causing the first reservoir This is a two-position solenoid valve that shuts off the passage 500 and the first pump passage 508 and turns them on when turned on. Further, SR _C-2 5 0 6 intercepts a second reservoir passage 5 0 2 and the second pump passage 5 1 0 by being turned off and connects them to each other by being turned on It is a two-position solenoid valve.

The first hydraulic chamber 220 and the second hydraulic chamber 222 of the master cylinder 218 have a first hydraulic passage 238 and a second hydraulic passage, respectively.

240 are in communication. The first hydraulic pressure passage 238 communicates with a first mass cut solenoid 512 (hereinafter, referred to as SMC—, 512). On the other hand, a second master cut solenoid 51 (hereinafter referred to as SMC-251) communicates with the _second hydraulic passage 240.

The first pump pressure passage 5 16 and the hydraulic pressure passage 5 18 provided corresponding to the left rear wheel RL communicate with the SMC- 5 12. The first pump pressure passage 516 communicates with a first pump solenoid 520 (hereinafter, referred to as SMV—, 520). Further, a hydraulic passage 522 provided corresponding to the right front wheel FR is communicated with the SMV,, 520. A constant pressure release valve 524 is provided inside the SMV-, 520.

520 is connected to the first pump pressure passage 5 16 and the fluid pressure passage 5 22 when turned off, and through the constant pressure release valve 5 24 when turned on. It is a two-position solenoid valve that allows them to communicate with each other. Between the first pump pressure passage 5 16 and the hydraulic pressure passage 5 22, only the flow of the fluid from the first pump pressure passage 5 16 to the hydraulic pressure passage 5 22 is restricted. Allowable check valves 5 2 6 are provided.

The second pump pressure passage 5 28 and the hydraulic pressure passage 5 30 provided corresponding to the right rear wheel RR communicate with the SMC-25 14. The second pump pressure passage 5 2 8 has a second pump solenoid 5 3 2 (hereinafter referred to as SMV— ₂ 5

3 2) are in communication. The SMV-2532 further communicates with a hydraulic passage 5334 provided for the left front wheel FL. A constant pressure release valve 536 is provided inside the SMV-25325. SMV— ₂ 532, when turned off, makes the second pump pressure passage 528 and the fluid pressure passage 5334 conductive, and when turned on, through the constant pressure release valve 536. It is a two-position solenoid valve that allows them to communicate with each other. Between the first pump pressure passage 528 and the hydraulic pressure passage 534, only the flow of the fluid flowing from the second pump pressure passage 528 to the hydraulic pressure passage 336 is restricted. Allowable check valves 5 3 8 are provided.

SMC-, inside the 5 1 2 and _SMC-2 5 1 4 are each constant pressure relief valves 5 4 0, 5 4 2 are provided. When the SMC-, 5 12 is turned off, the first hydraulic passage 2 38 and the hydraulic passage 5 18 (and the first pump pressure passage 5 16) are electrically connected to each other, and A two-position solenoid valve that connects them via a constant-pressure release valve 540 when turned on. Further, _SMC-2 5 1 4 is a second fluid pressure passage 2 4 0 and the fluid pressure passage 5 3 0 (and the second pump pressure passage 5 2 8) and a conducting state when it is turned off, and A two-position solenoid valve that connects them via a constant-pressure release valve 542 when turned on.

An inverse between the first hydraulic passage 238 and the hydraulic passage 518 allowing only a fluid flow from the first hydraulic E passage 238 to the hydraulic passage 518 A stop valve 5 4 4 is provided. Similarly, only the flow of the fluid from the second hydraulic passage 240 to the hydraulic passage 530 is allowed between the second hydraulic passage 240 and the hydraulic passage 530. A check valve 5 4 6 is provided.

Four hydraulic passages 5 16, 5 2 2, 5 2 8, 5 3 4 provided for the left and right front wheels and the left and right rear wheels are the same as in the fourth and fifth embodiments. The holding solenoid S ** H, the pressure reducing solenoid S ** R, the wheel cylinders 282 to 288 and the check valves 290 to 296 are connected to each other. Further, a first decompression passage 548 communicates with decompression solenoids SF RR 274 and SRLR 280 of the right front wheel FR and the left rear wheel RL. Further, a second decompression passage 550 is provided in the decompression solenoids SFLR 276 and S RRR 278 of the left front wheel FL and the right rear wheel RR. 539 C 9 5 Communication.

A first reservoir 552 and a second reservoir 55 communicate with the first decompression passage 548 and the second decompression passage 550, respectively. Further, the first reservoir 55 2 and the second reservoir 55 4 are connected to the suction side of the first pump 56 0 and the second pump 56 2 via check valves 55 6 and 55 58, respectively. It communicates with the suction side. The discharge side of the first pump 560 and the discharge side of the second pump 562 are in communication with dampers 564 and 566 for absorbing the pulsation of the discharge pressure. The dampers 564 and 566 communicate with the hydraulic passages 522 and 534, respectively.

Wheel speed sensors 330, 332, 334, 336 are arranged near each wheel. The ECU 210 detects the rotation speeds V and _v of each wheel based on the output signals of the wheel speed sensors 330 to 336. Further, a hydraulic sensor 338 is provided in the second hydraulic passage 240 communicating with the master cylinder 2 18. The ECU 210 detects the mass cylinder pressure P _{M / C} based on the output signal of the fluid pressure sensor 338.

(1) The normal braking function is realized by turning off all solenoid valves of the braking force control device as shown in Fig. 22. Hereinafter, the state shown in FIG. 22 is referred to as a normal brake state. The control for realizing the normal brake function in the braking force control device is called normal brake control.

In the normal brake state shown in FIG. 22, both the wheel cylinder 288 of the right front wheel FR and the wheel cylinder 288 of the left rear wheel RL are connected via the first hydraulic passage 238 to the master cylinder 218. The first hydraulic chamber 220 communicates with the first hydraulic chamber 220. The wheel cylinder 284 of the front left wheel FL and the wheel cylinder 286 of the rear right wheel RR are both in the second hydraulic passage 240. In this case, the master cylinder pressure P w / c of the wheel cylinders 282 to 288 always communicates with the master cylinder pressure P. It is controlled to equal pressure with _{M / C.} Therefore, according to the state shown in FIG. 22, the normal braking function is realized.

② In the ABS function, in the state shown in Fig. 22, the first pump 560 and the second pump 562 are turned on, and the holding solenoid S

This is realized by appropriately driving ** H and the decompression solenoid S ** R as required by the ABS. Hereinafter, the control for realizing the ABS function in the braking force control device is referred to as ABS control.

During the execution of the ABS control, the high hydraulic master cylinder pressure is applied to all four hydraulic passages 5 18, 5 22, 5 2 8, 5 3 4 provided for the left and right front wheels and the left and right rear wheels. P _{M / C} is derived. Therefore, if the holding solenoid S ** H is opened and the pressure reducing solenoid S ** R is closed under such circumstances, the wheel cylinder pressure P _{w / C} of each wheel must be increased. Can be. Hereinafter, also _c this state is referred to as (i) pressure increasing mode, during execution of the ABS control, both the holding Seo Leno I de S * * H and reduced pressure Sorenoi de S * * R When closed, The wheel cylinder pressure Pw / c of each wheel can be maintained. Hereinafter, this state is referred to as (ii) holding mode. Further, when the holding solenoid S ** H is closed and the pressure reducing solenoid S ** R is opened during the execution of the ABS control, the wheel cylinder pressure P _{w / C} can be decompressed. Hereinafter, this state is referred to as (iii) decompression mode.

During execution of the ABS control, the ECU 210 appropriately sets (i) the pressure increasing mode, (ii) the holding mode, and (iii) the pressure reducing mode as described above for each wheel. Holding solenoid S according to slip condition of each wheel

** H and decompression solenoid S ** R are controlled. When the holding solenoid S ** H and the depressurizing solenoid S ** R are controlled as described above, the wheel cylinder pressure P _{w / C of} all the wheels causes an excessive slip rate on the corresponding wheels. It is controlled to an appropriate pressure without any problem. This As described above, according to the above control, the ABS function can be realized in the braking force control device.

When the decompression mode is performed on each wheel during the execution of the ABS control, the brake fluid in the wheel cylinders 282 to 288 will cause the first decompression passage 548 and the second decompression passage 5 It flows into the first reservoir 55 2 and the second reservoir 55 4 through 50. The brake fluid flowing into the first reservoir 552 and the second reservoir 554 is pumped by the first pump 560 and the second pump 562 to the hydraulic passages 522, 534. Supplied.

Part of the brake fluid supplied to the hydraulic passages 52 2 and 5 3 4 flows into the wheel cylinders 282 to 288 when (i) the pressure increase mode is performed on each wheel. . The remainder of the brake fluid flows into the master cylinder 218 to compensate for the outflow of the brake fluid. Therefore, according to the system of the present embodiment, an excessive stroke does not occur on the brake pedal 2 12 during execution of the ABS control.

(3) As in the case of the fourth embodiment, after the driver performs the emergency braking operation, the BA function is appropriately set to (I) start pressure increase mode, (1 I) assist pressure increase mode, (1 1 [] Assist pressure reduction mode, GV) Assist pressure holding mode, (V) Assist pressure gradual increase mode, and (VI) Assist pressure gradual decrease mode are realized. This is realized by the ECU 210 controlling the braking force control device as described above. Hereinafter, the control for realizing the BA function in the braking force control device is referred to as BA control.

FIG. 23 shows an assist pressure increasing state realized during execution of the BA control. The assist pressure increase state is set when the wheel cylinder pressure P _{w / C} of each vehicle needs to be increased during the execution of the BA control, that is, during the execution of the BA control, the (I) start pressure increase mode is set. And (II) assist pressure increasing mode and (Ι Π) assist pressure gradual increasing mode.

In the system of the present embodiment, the assist pressure is increased during BA control. As shown in Fig. 23, the pressure state is

5 0 4, SRC-2 500, and mass cut solenoid SMC-, 5 1 2, SMC- ₂ 5 1 4 are turned on, and the first pump 5 60 and the second pump 5 6 This is realized by setting 2 to the ON state.

If the assist pressure increase state is realized during execution of the B A control, the brake fluid stored in the reservoir tank 2

60 and the second pump 56 2 pumps it up and supplies it to the hydraulic passages 52 2, 5 3 4. In the assist pressure increasing state, the fluid pressure passage 522, the wheel cylinder 282 of the right front wheel FR and the wheel cylinder 288 of the left rear wheel RL are maintained in a conductive state. In addition, in the assist pressure increasing state, the pressure in the hydraulic pressure passage 52 2 exceeds the valve opening pressure of the constant pressure release valve 5 40 until the pressure becomes higher than the master cylinder pressure PM _{/ C.} In this case, the flow of fluid from the hydraulic pressure passage 5222 to the mass cylinder 2118 is blocked by the SMC- and 512.

Similarly, in the assist pressure increasing state, the hydraulic pressure passage 534 and the foil cylinder 2884 of the left front wheel FL and the foil cylinder 2886 of the right rear wheel RR are maintained in a conductive state, and the hydraulic pressure is maintained. Until the internal pressure of passage 5334 exceeds the opening pressure of constant pressure release valve 542, and becomes higher than the mass cylinder pressure P _{M / C} , the master cylinder is The flow of fluid toward the 2nd 18 side is blocked by the SMC-25 14.

For this reason, when the assist pressure increasing state shown in FIG. 23 is realized, thereafter, the wheel cylinder pressure Pw / c of each wheel increases the hydraulic pressure of the first pump 560 or the second pump 562. As a pressure source, the pressure is immediately increased to a pressure exceeding the mass cylinder pressure PM / c. As described above, according to the assist pressure increasing state shown in FIG. 23, the braking force can be quickly raised. By the way, in the assist pressure increasing state shown in FIG. 23, the hydraulic passages 5 18, 5 2 2, 5 3 4, 5 3 0 are connected to the master cylinder via check valves 5 4 4, 5 4 6. It communicates with 2 1 8. Therefore, when the master cylinder pressure P _{M / C} is higher than the wheel cylinder pressure P _{w / C} of each wheel In the BA operation state, the wheel cylinder pressure Pw / C can be increased using the master cylinder 218 as a hydraulic pressure source.

FIG. 24 shows an assist pressure holding state realized during execution of the BA control. The assist pressure holding state is set when the wheel cylinder pressure P _W / _C of each wheel needs to be held during the execution of the BA control, that is, the (IV) assist pressure holding mode is required during the BA control. Is realized when As shown in Fig. 24, the master pressure holding state is such that the mass cut solenoids SMC-, 5 12 and SMC ₂ 5 14 are turned on and the first pump 56 is turned on. This is realized by turning on the 0 and the second pump 562.

In the assist pressure holding state shown in FIG. 24, the first pump 560 and the reservoir tank 224, and the second pump 562 and the reservoir tank 224 force, the SRC-1504 and the SRC— It is cut-off state by ₂ 5 0 6. Therefore, in the assist pressure holding state, the fluid is not discharged from the first pump 560 and the second pump 562 to the hydraulic pressure passages 522, 534. Further, Assist in pressure holding state, hydraulic pressure passage 5 1 8, 5 2 2 and 5 3 0, 5 3 4 forces ,, respectively S MC-, 5 1 2 and _SMC-2 5 1 shown in FIG. 2 4 It is virtually separated from the mass cylinder 2 18 by 4. Therefore, according to the assist pressure holding state shown in FIG. 24, the wheel cylinder pressure P _{w / C} of all the wheels can be held at a constant value.

FIG. 25 shows a reduced assist pressure state realized during the execution of the BA control. The assist pressure reduction state is required when it is necessary to reduce the wheel cylinder pressure Pw / c of each wheel during execution of the BA control, that is, during the BA control, the (Π [) assist pressure reduction mode and (Vi) This is realized when execution of the assist pressure mode is requested. The assist pressure reduction state is realized by turning on the first pump 560 and the second pump 562 as shown in FIG.

In the assist pressure reduced state shown in FIG. 25, the first pump 560 and the The second pump 562 is disconnected from the reservoir tank 224. Therefore, fluid is not discharged from the first pump 562 and the second pump 562 to the hydraulic pressure passages 522, 534. Further, in the assist pressure reduced state, the wheel cylinders 282-288 of each wheel and the mass cylinder 2188 are in a conductive state. Therefore, if the assist pressure reduction state is realized, the wheel cylinder pressure Pw / c of all wheels can be reduced using the mass cylinder pressure PM / C as the lower limit.

As described above, according to the assist pressure increasing state, the assist pressure holding state, and the assist pressure decreasing state shown in FIGS. 23 to 25, the wheel cylinder pressure can be appropriately adjusted according to the BA control request. It is possible to increase, maintain, and reduce the pressure of P _{w / C.} For this reason, the BA function can also be realized by the braking force control device of the present embodiment, similarly to the case of the above-described fourth embodiment.

In the braking force control device according to the present embodiment, when the above-described BA control is started, the wheel cylinder pressure P _{w / C of} each wheel is immediately increased, so that an excessive slip is applied to any of the wheels. In some cases, the rate may increase. In such a case, the ECU 210 starts the BA + ABS control. Hereinafter, the operation of the braking force control device associated with the execution of the BA + ABS control will be described with reference to FIGS. 23 to 25 as well as FIGS. 26 and 27.

In the braking force control device of the present embodiment, when the driver performs a braking operation intended to reduce the braking force during the execution of the BA + ABS control, the wheel cylinder pressure Pw / c of the ABS target wheel is increased by the ABS. It is necessary to reduce the wheel cylinder pressure P _{w / C} of the non-ABS wheels toward the cylinder pressure P _{M / C} while controlling the pressure according to the control requirements. Hereinafter, this request is referred to as the assist pressure reduction ABS request.

Assist pressure depressurizing ABS request, while realizing the assist pressure depressing state shown in Fig. 25 above, of the holding solenoid S ** H and depressurizing solenoid S ** R, the ABS Key to control It is realized by appropriately controlling according to the demand. Hereinafter, a state in which the above control is performed in the braking force control device is referred to as an assist pressure reduction ABS state.

The assist pressure reduction ABS request is generated when the driver intends to reduce the braking force, that is, when it is not necessary to increase the wheel cylinder pressure P _{w / C of} any of the wheels. Thus, in a situation where Assist pressure reducing AB S request has occurred, while depressurizing the Hoirushiri emissions Da pressure Pw / c of the ABS non-subject wheel, holding and pressure reduction the Hoirushiri Nda圧P _{w /} c of the ABS subject wheel You need to be able to do it.

In the above assist pressure reduction ABS state, all the holding solenoids S ** H communicate with the master cylinder 218. For this reason, according to the assist pressure reduction ABS state, the wheel cylinder pressure Pw / c of the ABS non-target wheel can be appropriately reduced toward the master cylinder pressure PM / C. Further, in this situation, when the (ii) holding mode or the (iii) decompression mode is realized for the ABS target wheel, the wheel cylinder pressure Pw / c of the ABS target wheel can be held or reduced. As described above, according to the assist pressure reduction ABS state described above, the function to be realized when the assist pressure reduction ABS request occurs can be appropriately realized.

In the braking force control device of the present embodiment, when the driver performs a braking operation intended to increase the braking force during execution of the BA + AB S control, the wheel cylinder pressure Pw / c of the ABS target wheel is changed to AB It is necessary to increase the wheel cylinder pressure Pw / c of the non-ABS wheels in a region exceeding the master cylinder pressure P _M / c while controlling the pressure according to the S control request. Hereinafter, this requirement is referred to as an assist pressure increase ABS requirement.

Assist pressure boost ABS requirements are to increase the assist pressure increase state shown in Fig. 23 above, and to use the holding solenoid S ** H and the pressure reduction solenoid S ** R that correspond to the ABS target wheel. It can also be realized by controlling according to control requirements. That is, For example, if the left rear wheel RL is a wheel to be subjected to ABS, the SRLH 27 2 and 3 measuring length 280 are required for ABS control while achieving the assist pressure increasing state shown in Fig. 23 above. if according to the control, while controlling the wheel Rushiri Nda圧Pw / c of the left rear wheel RL in pressure in response to a request AB S control. other wheels FL, FR, the Hoirushiri Nda圧P _{w / C} of RL The pressure can be increased in a region higher than the master cylinder pressure PM _{/ C.}

However, when the ABS control is started for the left rear wheel RL, the holding solenoid SR LH272 corresponding to the left rear wheel RL thereafter executes (i) the pressure increase mode for the left rear wheel RL. The valve is closed except for a short time. For this reason, after the ABS control is started for the left rear wheel RL, most of the brake fluid discharged from the first pump 560 is applied to the wheel cylinder 282 of the right front wheel FR, which is a wheel not subject to ABS. Inflow.

The discharge capacity of the first pump 560 is such that the wheel cylinder pressure Pw / c of the right front wheel FR and the wheel cylinder pressure Pw / c of the left rear wheel RL can be simultaneously increased with an appropriate pressure increase gradient. Is set to For this reason, under the condition that most of the brake fluid discharged from the first pump 560 flows into the wheel cylinder 282 of the right front wheel FR, which is a non-ABS target wheel, the wheel cylinder pressure P of the right front wheel FR Excessive pressure gradient occurs in _{w / C.}

Further, as described above, in a situation where an excessive pressure increase gradient is generated in the wheel cylinder pressure Pw / c of the right front wheel FR, when (i) the pressure increase mode is executed for the left rear wheel RL, the left rear wheel A situation in which the foil cylinder pressure Pw / c of the RL is excessively increased, that is, a situation in which hunting easily occurs in the ABS control is formed.

In this regard, while realizing the assist pressure increasing state shown in Fig. 23 above, the holding solenoid S ** H and the depressurizing solenoid S ** R that correspond to the ABS target wheel are required for the ABS control. The method of satisfying the ABS demand by increasing the assist pressure by controlling according to This is not necessarily the optimal method for achieving BA + ABS control in a force control device.

Fig. 26 shows the state realized by the braking force control device when an assist pressure boost ABS request is made with the left rear wheel RL as the ABS target wheel (hereinafter referred to as the assist pressure boost ABS state). 1 shows an embodiment. The assist pressure increase ABS state in which the left rear wheel RL is the ABS target wheel is realized by controlling the braking force control device so that the following conditions (a) to (d) are satisfied.

(a) The first reservoir cut solenoid SR504, which is turned on in the assist pressure increasing state shown in FIG. 23, is turned off. Specifically, (a- 1) second reservoir one Baka' Totsurenoi de SRC - ₂ 5 0 6, and the mass evening mosquito Tsu preparative source Reno I de SMC, 5 1 2, SMC - 25 1 4 The O emissions state And (a-2) the front pump 310 and the rear pump 312 are turned on.

(b) The holding solenoid SRLH272 and the decompression solenoid SRLR280 of the left rear wheel RL, which is the ABS target wheel, are controlled as follows in accordance with the request of the ABS control. (B-1) When (ii) holding mode and (iii) depressurization mode are required by ABS control, control is performed in the same manner as when ABS control is executed alone. (B-2) When the pressure increase mode is requested by the ABS control (i) When the pressure increase mode is requested, the pressure increase mode is executed for a predetermined time shorter than when the ABS control is executed alone. I do.

(d) Turn off the master cut solenoid SMC-, 512 belonging to the system including the left rear wheel RL, which is the ABS target wheel, for the left rear wheel RL (iii) In synchronization with the time when the decompression mode is executed State (valve open state). According to the above condition (a), when an assist pressure increase ABS request occurs, At the same time, the first pump 560 and the reservoir tank 224 belonging to the system including the ABS target wheel can be shut off. In this case, since the brake fluid sucked into the first pump 560 is limited to the fluid flowing out of the wheel cylinder 288, the hydraulic pressure generated on the discharge side of the first pump 560 is compared. It is suppressed to extremely low pressure. As a result, an advantageous state is formed to prevent hunting of the ABS control and to suppress the pressure increase gradient of the wheel cylinder pressure P _{w / C} of the right front wheel FR, which is a wheel not subject to ABS. .

According to the above condition (b), the time during which (i) the pressure increase mode is executed in the left rear wheel RL, which is the ABS target wheel, is reduced as compared with the case where the ABS control is executed alone. (I) When the execution time of the pressure increase mode is shortened, (i) the pressure increase amount generated in the wheel cylinder pressure P _W / c of the left rear wheel RL due to the execution of the pressure increase mode is suppressed. . In such a situation, hunting is unlikely to occur in the ABS control even if a higher hydraulic pressure is generated upstream of the SRLH 272 than normal.

According to the condition (c) above, for the right front wheel FR belonging to the same system as the ABS target wheel, the state where the brake fluid flows into the wheel cylinder 282 and the state where the brake fluid is blocked are determined. It is repeated at the duty ratio of. In this case, the wheel cylinder pressure Pw / c of the right front wheel FR increases with an appropriate pressure increase gradient even if a higher hydraulic pressure is generated upstream of the SFRH 266 than usual.

According to the condition (d), the brake fluid flowing out of the foil cylinder 288 and the discharge side of the first pump 560 are mass-synchronized with the time when the brake fluid is pumped by the first pump 560. The evening cylinder 218 is brought into conduction. In this case, since the brake fluid can flow into the mass cylinder 218, the hydraulic pressure generated on the discharge side of the first pump 560 is suppressed to a relatively low pressure. As a result, an advantageous state is formed to prevent hunting of the ABS control and to suppress the pressure increase gradient of the wheel cylinder pressure Pw / c of the right front wheel FR, which is a non-ABS target wheel. For this reason, according to the above assist pressure increase ABS state, the wheel cylinder pressure Pw / c of the ABS target wheel can be controlled in the same manner as when the ABS control is executed alone, The wheel cylinder pressure P _{w / C} of the wheel not subject to ABS is increased with the same pressure increase gradient as when the wheel cylinder pressure P _{w / C} is required to be increased under the condition that BA control is executed alone. Can be done. As described above, according to the above-described assist pressure increasing ABS state, the function to be realized when the assist pressure increasing ABS request is generated can be appropriately realized.

In the braking force control device of the present embodiment, when the driver performs a braking operation intended to maintain the braking force during the execution of the BA + ABS control, the wheel cylinder pressure P _{w / C} of the ABS target wheel is controlled. It is necessary to maintain the wheel cylinder pressure P _{w / C} of the non-ABS wheels while controlling the pressure to the pressure according to the ABS control requirements. Hereinafter, this request is referred to as an assist pressure holding ABS request.

When the assist pressure holding ABS request is generated, while maintaining the assist pressure holding state shown in Fig. 2 above, the holding solenoid S ** H and the decompression solenoid S ** R By controlling the corresponding components according to the ABS control requirement, the wheel cylinder pressure P _{w / C} of the ABS target wheel can be controlled to the pressure required by the ABS control, and the same system Thus, the wheel cylinder pressure Pw / c of the ABS non-target wheels belonging to the system that does not include the ABS target wheels can be maintained.

That is, for example, when an assist pressure holding ABS request is made for the left rear wheel RL as an ABS target wheel, the SRLH272 and SRLR 280 are controlled by the ABS control while realizing the assist pressure holding state shown in FIG. If controlled as required, for the left rear wheel RL, (ii) holding mode and (iii) depressurizing mode, and (i) increasing pressure mode using the first pump 560 as the hydraulic pressure source can do. Therefore, the left rear wheel The RL wheel cylinder pressure Pw / c can be controlled according to the ABS control requirements. In the above situation, the rear wheel system not including the ABS target wheel is maintained in the same manner as the state shown in FIG. Therefore, the wheel cylinder pressure P _{w / c} can be maintained for the front left wheel FL and the rear right wheel RR, as in the case where the BA control is performed alone.

However, according to the above method, the brake fluid flowing out of the wheel cylinder 288 is pumped by the first pump 560 after the pressure reduction mode is executed for the left rear wheel RL, and the right front wheel It flows into the FR foil cylinder 282. For this reason, the right front wheel FR belonging to the front wheel system having an ABS target wheel in the same system cannot meet the requirements of the BA control, that is, cannot maintain the wheel cylinder pressure P _{w / C.}

Fig. 27 shows an example of a state (hereinafter referred to as an assist pressure holding ABS state) realized in the braking force control device when an assist pressure holding ABS request is made with the left rear wheel RL as an ABS target wheel. Is shown. The assist pressure holding ABS state in which the left rear wheel RL is the ABS target wheel is realized by controlling the braking force control device so that the following conditions (e) to (g) are satisfied.

( _e ) Of the holding solenoids S ** H that are off in the assist pressure holding state shown in Fig. 24 above, the right front wheel FR, which is an ABS non-target wheel that has ABS target wheels in the same system, Turn the holding solenoid SF RH266 on (closed). Specifically, (e- 1) Ma scan evening cut Tosorenoi de SMC-, 5 1 2, _SMC-2 5 1 4 a is turned on, _(e -2) first pump 5 6 0 and a second pump 5 62 is turned on, and (e-3) SFRH 266 is turned on.

(0 The holding solenoid SRLH 272 and the depressurizing solenoid SRLR 280 of the left rear wheel RL, which is the ABS target wheel, are subjected to the ABS control request in the same manner as in the above condition), that is, (i) Booster mode Is controlled by a pattern in which the maintenance time of the node is shortened compared to the normal time.

(g) The first mastercut solenoid 521 belonging to the system including the left rear wheel RL, which is the ABS target wheel, is subjected to the same method as the above condition (c), that is, for the left rear wheel RL, Control so that it is turned off (opened) in synchronization with the time when the pressure reduction mode is executed. According to the above condition (e), the wheel cylinder 282 of the right front wheel FR, which is a non-ABS target wheel, is connected to the system including the ABS target wheel at the same time when the assist pressure increase ABS request is generated. Can be disconnected from pump 560. In this case, since the brake fluid discharged from the first pump 560 does not flow into the wheel cylinder 282, the wheel cylinder pressure P w / c of the right front wheel FR is appropriately maintained according to the BA control request. .

According to the condition (O), as in the case where the condition (b) is realized, (i) when the pressure increase mode is executed on the left rear wheel RL, which is the ABS target wheel, The amount of pressure increase that occurs in the foil cylinder pressure _PW / _C can be suppressed.

Further, according to the condition (g), the brake fluid flowing out of the wheel cylinder 288 is pumped by the first pump 560 as in the case where the condition (d) is realized. In synchronization with the timing, the discharge side of the first pump 560 and the master cylinder 218 can be brought into conduction.

Therefore, according to the above-described assist pressure holding ABS state, the wheel cylinder pressure P _{w / C} of the ABS target wheel can be controlled in the same manner as in the case where the ABS control is executed alone, and all the ABS non-control operations are performed. The wheel cylinder pressure P _{w / C} of the target wheel can be appropriately maintained as in the case where the BA control is executed alone. As described above, according to the assist pressure holding ABS state described above, the function to be realized when the assist pressure holding ABS request is generated can be appropriately realized. According to the braking force control device of the present embodiment, the ABS control is executed independently. In this case, the states shown in FIGS. 22 to 27 are realized as appropriate in accordance with the case where the BA control is executed independently and the case where the BA + ABS control is executed. You. Therefore, according to the braking force control device of the present embodiment, when the ABS control or the BA control is executed independently, the wheel cylinder pressure P _{w / C} is controlled to an appropriate hydraulic pressure according to those requirements. When the BA + ABS control is executed, the wheel cylinder pressure Pw / c of the ABS target wheel is changed to the pressure required by the ABS control, and the wheel cylinder pressure of the ABS non-target wheel is changed. The pressure P _{w / C} can be precisely controlled to the pressure required by BA control.

By the way, in the above embodiment, only when the (iii) decompression mode is executed on the ABS target wheel during the execution of the BA + ABS control, the master power train belonging to the same system as that wheel is used. SMC-, 5 1 2, although the fact that the _SMC-2 5 1 4 open state, the present invention is not limited to this, during execution of the BA + ABS control, and always open state thereof You may do it.

Note that, in the above embodiment, the first pump 560 and the second pump 562 serve as the “assist pressure generating means” in the hydraulic pressure passages 5 18, 5 2 2, 5 3 0, 5 3 4 to but "high pressure passage", first Masutakatsu Tosorenoi de S MC 5 1 2 and the second Masutakatsu Totsurenoi de _SMC-2 5 1 4 forces the "operation liquid Atsuryoku' preparative mechanism", the first pressure decreasing passage 5 4 8 and the second The decompression circuit 550 corresponds to the “low pressure passage”, and the first reservoir 552 and the second reservoir 554 correspond to the “low pressure source” and the “second low pressure source”, respectively.

Claims

The scope of the claims

1. Hydraulic pressure reduction control that controls the wheel cylinder pressure while the hydraulic pressure inflow path communicating with the wheel cylinder is blocked, and braking that is greater than normal when emergency braking is performed by the driver In a braking force control device that executes a brake assist control that generates hydraulic pressure,

Continuity detecting means (step 104) for detecting the continuity of the hydraulic pressure flow path (56, 62) of the foil cylinder;

If the hydraulic pressure inflow path of any one of the wheel cylinders is substantially blocked at the start of the brake assist control, the hydraulic pressure inflow is suppressed to suppress the inflow of the brake hydraulic pressure to another wheel cylinder. Means (step 108) and

A braking force control device comprising:

2. When the characteristic value related to the slip state of the wheel exceeds a predetermined threshold value, pressure reduction control for reducing the wheel cylinder pressure while the hydraulic pressure inflow path communicating with the wheel cylinder of the wheel is cut off is performed. After execution, a brake fluid pressure control for executing a predetermined fluid pressure control on the wheel cylinder, and a brake assist control for generating a larger brake fluid pressure than usual when an emergency brake operation is performed by the driver. In the braking force control device that executes

A continuity detecting means (step 11) for detecting the continuity of the hydraulic pressure inflow path (56, 62) of the foil cylinder;

When the brake assist control is started in a state where the hydraulic pressure inflow path of any one of the foil cylinders is substantially blocked, the pressure reduction control is executed for the at least one other wheel cylinder. Means for changing the depressurization tendency (step 1 18), in which the decompression tendency caused by A braking force control device comprising:

3. The braking force control device according to claim 2,

When the brake assist control is started in a state in which the hydraulic pressure inflow path (56, 62) of any one of the foil cylinders is substantially interrupted, the above-described operation of the at least one other foil cylinder is performed. A braking force control device comprising threshold value changing means (step 118) for setting a threshold value smaller than a normal value.

4. Brake assist control, which generates a larger braking oil pressure than usual when an emergency braking operation is performed by the driver, and reduces the braking oil pressure of each wheel to a pressure that does not generate an excessive slip rate on each wheel. In the anti-lock brake control to control and the braking force control device to execute

Operating hydraulic pressure generating means (2 18) for generating brake hydraulic pressure according to the brake operation amount;

Assist pressure generating means (310, 312; 560, 562) for generating a predetermined brake fluid pressure irrespective of the brake operation amount;

A high-pressure passage (248, 250, 252; 518, 522, 530, 534) communicating with both the operating fluid pressure generating means and the assist pressure generating means; ,

An operating fluid pressure cut-off mechanism (242, 244: 512, 514) capable of shutting off the operating fluid pressure generating means and the high-pressure passage;

A low-pressure passage (298, 300: 548, 550) communicating with a predetermined low-pressure source (302, 304: 552, 554);

A conduction state control mechanism (266-280) for controlling a conduction state between the wheel cylinder of each wheel and the high-pressure passage and a conduction state between the wheel cylinder of each wheel and the low-pressure passage;

When an emergency brake operation is performed by the driver, the operation fluid BA control means for causing the pressure cut mechanism to be in a cutoff state, and for supplying a predetermined brake fluid pressure to the high-pressure passage from the assist pressure generation means, and controlling the conduction state control mechanism in a predetermined control pattern. Thus, the ABS control means (FIG. 20 routine) for controlling the wheel cylinder pressure of each wheel so that an excessive slip ratio does not occur on each wheel, and the anti-lock brake control are executed independently. When the anti-lock brake control and the brake assist control are being executed simultaneously, the control pattern is increased to suppress the increase in the wheel cylinder pressure. ABS control pattern selection means (FI G. 20 routine) for pressure suppression pattern;

A braking force control device comprising:

5. Brake assist control that generates a larger brake oil pressure than usual when an emergency brake operation is performed by the driver, and a pressure at which the brake oil pressure of each wheel does not generate an excessive slip rate on each wheel In the anti-lock brake control that controls the pressure and the braking force control device that performs the pressure,

Means for generating an assist pressure (310, 312; 560, 562) for generating a predetermined brake fluid pressure regardless of the brake operation amount;

High pressure passages (248, 250, 25: 518, 522, 5330, 5334) communicating with both the operating hydraulic pressure generating means and the assist pressure generating means When,

An operating hydraulic pressure cut-off mechanism (24, 24, 4; 512, 514) that can shut off the operating hydraulic pressure generating means and the high-pressure passage;

A low pressure passage (298, 300: 548, 550) communicating with a predetermined low pressure source (302, 304: 552, 554); A conduction state control mechanism (266-280) for controlling a conduction state between the wheel cylinder of each wheel and the high-pressure passage, and a conduction state between the wheel cylinder of each wheel and the low-pressure passage;

BA control means for shutting off the operating hydraulic pressure cut-off mechanism when an emergency brake operation is performed by a driver, and for supplying predetermined brake hydraulic pressure to the high-pressure passage from the assist pressure generating means; By controlling the conduction state control mechanism according to a predetermined control pattern, ABS control means (FIG. 1) for controlling the wheel cylinder pressure of each wheel so that an excessive slip ratio does not occur in each wheel. 20 routine), and when the brake assist control and the anti-braking brake control are executed simultaneously, the increasing gradient of the wheel cylinder pressure of the wheels not to be subjected to the anti-braking brake control is suppressed. BA pressure increase gradient suppression means (a routine of FIG. 19) for controlling the conduction state control mechanism provided corresponding to the non-target wheel;

A braking force control device comprising:

6. Brake assist control, which generates a larger brake oil pressure than usual when an emergency brake operation is performed by the driver, and reduces the brake oil pressure of each wheel to a pressure that does not generate an excessive slip rate on each wheel. In the anti-lock brake control to control and the braking force control device to execute

Low-pressure passages (298, 300: 548, 5) communicating with the first low-pressure source (224) and the second low-pressure source (302, 304; 552, 554). 5 0)

Assist pressure generating means (310, 316: 560, 562) for generating a predetermined brake fluid pressure irrespective of the brake operation amount by pumping the brake fluid sucked from the low-pressure passage. When, A high-pressure passage (248, 250, 252: 518, 522, 530, 534) communicating with both the operating fluid pressure generating means and the assist pressure generating means; ,

An operation hydraulic pressure cut mechanism (24, 2, 24, 4: 5, 12, 14) that can shut off the operation hydraulic pressure generation means and the high pressure passage;

BA control means for shutting off the operating hydraulic pressure cut-off mechanism when an emergency brake operation is performed by a driver, and for supplying predetermined brake hydraulic pressure to the high-pressure passage from the assist pressure generating means; By controlling the conduction state control mechanism according to a predetermined control pattern, ABS control means (FIG. 1) for controlling the wheel cylinder pressure of each wheel so that an excessive slip ratio does not occur in each wheel. 20) and the low pressure source cutting means for shutting off the first low pressure source and the assist pressure generating means when the brake assist control and the antilock brake control are simultaneously executed. (A routine of FIG. 18) A braking force control device comprising:

7. Brake assist control that generates a larger brake oil pressure than normal when an emergency brake operation is performed by the driver, and a pressure at which the brake oil pressure of each wheel does not generate an excessive slip rate on each wheel In the anti-lock brake control that controls the pressure and the braking force control device that performs the pressure,

Assist pressure generating means (310, 312: 560, 562) for generating a predetermined braking fluid pressure regardless of the brake operation amount;

Linked to both the operating fluid pressure generating means and the assist pressure generating means. High-pressure passages (248, 250, 252; 518, 52, 52, 53, 53)

An operating hydraulic pressure cut mechanism (24, 24, 24: 51, 24) that can shut off the operating hydraulic pressure generating means and the high-pressure passage;

A conduction state control mechanism (266-280) for controlling a conduction state between the wheel cylinder of each wheel and the high-pressure passage, and a conduction state between the wheel cylinder of each wheel and the low-pressure passage;

BA control means for shutting off the operating hydraulic pressure cutoff mechanism when an emergency brake operation is performed by a driver, and for supplying predetermined brake hydraulic pressure to the high-pressure passage from the assist pressure generating means; By controlling the conduction state control mechanism according to a predetermined control pattern, an ABS control means (FIG. 2) for controlling the wheel cylinder pressure of each wheel so as not to generate an excessive slip rate on each wheel. 0 routine), and high-pressure passage opening means for turning on the operating hydraulic pressure cutting mechanism when the brake assist control and the anti-braking brake control are simultaneously executed;

A braking force control device comprising:

8. The braking force control device according to claim 6,

When the brake assist control and the anti-lock brake control are performed simultaneously and the wheel cylinder pressure is reduced at the target wheel for the anti-lock brake control, the operation hydraulic cut mechanism is turned on. A braking force control device comprising high-pressure passage opening means for setting a state.